End of Life Law in Australia

Capacity and Consent to Medical Treatment

Adults with decision-making capacity have the right to decide what can be done to their bodies. This means they can consent to medical treatment or refuse it. An adult who has capacity is said to be 'competent'.

This page explores the law relating to consent to treatment, including in an emergency situation, and when an adult will have capacity to make decisions about medical treatment. Information about the law in each State and Territory is discussed below.

The law on consent to treatment for children is different from the law about adults. For information about the law relating to children and consent to treatment visit the Children and end of life decision-making page.

When is a person’s consent to treatment not required?

Generally, health professionals should obtain a person’s consent prior to giving treatment, or undertaking any clinical test or medical examination.

Examples of when a person’s consent is not required include when:

  • he or she has impaired decision-making capacity. In this situation, consent can be provided in an Advance Care Directive or by a substitute decision-maker; or
  • emergency treatment is needed to save the life of or prevent serious injury to a person without capacity, and it is not possible to obtain a substitute decision-maker's consent. This is discussed further below.

Decision-making capacity

When will a person have capacity?

The law presumes that all adults have capacity to consent to or refuse treatment, unless it is shown otherwise.

The common law test is that a person will have capacity to make decisions about medical treatment if they are able to:

  • comprehend and retain the information needed to make the decision, including the consequences of the decision; and
  • use and weigh that information when deciding.

Relevant information about treatment includes the proposed treatment and alternatives, and the consequences and risks of different treatment options.

Guardianship and medical treatment legislation in the different States and Territories also establishes specific capacity tests and recognises the need for consent to treatment. Most are similar to this common law approach but some have additional requirements. Find out more about State and Territory laws on capacity below.

What if a person is making decisions that others disagree with?

An adult with capacity can make decisions that others disagree with. This includes a decision to refuse life-sustaining medical treatment which is clinically recommended (this issue was considered in the case of Re B (Adult: Refusal of Medical Treatment).

This is because capacity is assessed in relation to a person’s ability to make a decision and not what decision they make. However, unwise or unusual decisions may be a prompt to check a person’s capacity. If doubts remain after further assessment, a court or tribunal can be asked to assess a person’s capacity.

Can a person’s capacity be different for different decisions and change over time?  

A person may have capacity to make some decisions but not others. For more serious decisions, such as refusing life-sustaining treatment, the process of understanding, retaining and weighing the information (and risks involved) will be more complex than for more minor decisions, such as consenting to a flu vaccine.

Assessments of capacity are made in relation to the decision to be made so a finding of total incapacity is not common (except, for example, when a person is unconscious).

A person’s capacity to make a decision can also change over time. For example, a person may have fluctuating capacity because of some forms of dementia or mental illness.

Capacity will be judged at the time a treatment decision is required. For example, in Re C (Adult: Refusal of Medical Treatment) the Court decided that a person’s mental illness did not affect his decision-making capacity in relation to life-sustaining treatment.

Capacity and consent by State and Territory

In addition to the common law, each Australian State and Territory has guardianship and/or medical treatment legislation about capacity and consent. This legislation varies across jurisdictions and can be complex. In some jurisdictions, there are multiple definitions of capacity and which one applies depends on the context e.g. whether a person can make decisions about medical treatment decision-making, or if they need to have a guardian appointed. This has happened because some States and Territories have more than one piece of legislation that applies, and some of those laws were passed by parliaments at different times.

Click on the options below to read about the specific legislation in your State or Territory on capacity and consent, including:

  • when a person will have decision-making capacity;
  • the different contexts in which capacity is relevant (and the meaning of capacity in those contexts); and
  • when consent does not have to be obtained.

Australian Capital Territory

Decision-making capacity

A person is presumed to have capacity to make health care decisions.

There are two contexts in which capacity is relevant, and the test for capacity differs in each:

  • capacity for a Health Direction or Enduring Power of Attorney; and
  • capacity relating to consent to medical treatment by a guardian or health attorney.

Capacity for a Health Direction or Enduring Power of Attorney

A person has decision-making capacity to make a Health Direction or Enduring Power of Attorney if they:

  • can make decisions in relation to their own affairs; and
  • understand the nature and effect of the decisions.

A person has impaired decision-making capacity if they cannot do this. Further guidance on matters a person would need to understand to have capacity to make an Enduring Power of Attorney are included in section 17 of the Powers of Attorney Act 2006 (ACT).

A person does not have impaired decision-making capacity merely because of certain attributes or behaviours e.g. they are eccentric; make unwise decisions; have particular political or religious opinions, or sexual preferences; are a particular sexual orientation; engage in illegal or immoral conduct; or take drugs (including alcohol). However, any effect of drug-taking on the person may be taken into account in deciding whether they have impaired decision-making capacity.

A Health Direction will take effect both when a person has decision-making capacity, or impaired decision-making capacity. For further information about Health Directions visit the Australian Capital Territory Advance Care Directives page. For further information about Enduring Powers of Attorney visit the Public Trustee and Guardian.

Capacity and medical treatment decision-making by guardians and health attorneys

Where a person’s ability to make a medical treatment decision is impaired, the decision will need to be made by a substitute decision-maker (e.g. a guardian or health attorney).

Impaired decision-making ability means the person’s decision-making ability is impaired because of a physical, mental, psychological or intellectual condition or state, whether or not a diagnosable illness. A person will not have one of these conditions merely because they possess certain attributes or behaviours (examples of these are discussed above).

Where a person has impaired decision-making ability for a matter relating to their health or welfare, a guardian may be appointed by the Australian Capital Territory Civil and Administrative Tribunal to make medical treatment decisions. For further information visit the Public Trustee and Guardian.

A protected person is a person with impaired decision-making ability for giving consent to medical treatment who does not have:

  • an attorney under an Enduring Power of Attorney; or
  • a guardian with authority to provide that consent.

Where a protected person needs medical treatment, a health attorney may provide consent to that treatment. For information about who may be a person's health attorney visit the Australian Capital Territory Treatment Decisions page.

When consent to treatment is not required

Generally consent is not required to carry out emergency treatment on a person without capacity. However, it is good clinical practice to obtain a substitute decision-maker’s consent if possible and time permits. This is discussed further below and on the Australian Capital Territory Treatment Decisions page.

New South Wales

Decision-making capacity

Under the common law a person is presumed to have decision-making capacity for medical treatment decisions.

There are two contexts in which capacity is relevant, and the test for capacity differs in each:

  • capacity for medical treatment decision-making; and
  • capacity for appointing a guardian.

Capacity for medical treatment decision-making

The Guardianship Act 1987 (NSW) does not define ‘capacity’, ‘decision-making capacity’ or ‘decision-making ability’. It recognises however that a person will be ‘incapable of giving consent’ to medical treatment if the person cannot:

  • understand the general nature and effect of the proposed treatment; or
  • indicate whether or not he or she does or does not consent to the treatment being carried out.

Where this occurs, and the person does not have a common law Advance Care Directive which provides directions about medical treatment, a substitute decision-maker (e.g. a guardian or another person responsible) may need to make the treatment decision on that person’s behalf. For further information visit the New South Wales Treatment Decisions page.

Capacity relating to guardianship

A guardian can be appointed to make a range of personal decisions for an adult, including medical treatment decisions. A guardian will only be appointed (and their appointment will only be effective) if the person is ‘in need of a guardian’. This will occur where a person, because of a disability, it totally or partially incapable of managing themselves. A ‘person with a disability’ is a person who is:

  • intellectually, physically, psychologically or sensorily disabled;
  • of advanced age;
  • a mentally ill person within the meaning of the Mental Health Act 2007; or
  • otherwise disabled,

and as a result is restricted in one or more major life activities to such an extent that he or she requires supervision or social habilitation.

For further information visit the New South Wales Civil and Administrative Tribunal.

When consent to treatment is not required

Generally consent is not required to carry out emergency treatment on a person without capacity. However, it is good clinical practice to obtain a substitute decision-maker’s consent if possible and time permits. This is discussed further below and on the New South Wales Treatment Decisions page.

Minor treatment may also be carried out without consent if there is not a default decision-maker available or willing to make a decision. Minor treatment is treatment that is not special treatment (e.g. sterilisation), major treatment, or treatment in a clinical trial.

Major treatment includes a wide range of treatments listed in section 10 of the Guardianship Regulation 2016 (NSW), including any treatment that involves a substantial risk to the person of: death, brain damage, paralysis, loss of function of an organ or limb, permanent and disfiguring scarring, an unusually prolonged period of recovery, or a high level of pain or stress.

Northern Territory

Decision-making capacity

A person is presumed to have capacity to make health care decisions.

There are two contexts in which capacity is relevant, and the test for capacity differs in each:

  • capacity for an Advance Personal Plan; and
  • capacity relating to guardianship.

Capacity for an Advance Personal Plan

A person will have planning capacity if they have decision-making capacity for making an Advance Personal Plan, and they do not have a guardian.

A person will have decision-making capacity if they can:

  • understand and retain information about the matter;
  • weigh the information in order to make a decision; and
  • communicate that decision in some way.

If a person does not meet these requirements they will have impaired decision-making capacity, and a previously made Advance Personal Plan may apply. For further information visit the Northern Territory Advance Care Directives page.

Capacity relating to guardianship

A guardian may be appointed where a person has impaired decision-making capacity. A person’s decision-making capacity will be impaired where the person cannot:

  • understand and retain information about the person's personal and financial matters;
  • weigh the information to make reasoned and informed decisions about those matters; and
  • communicate those decisions in some way.

A person’s capacity may be impaired even if:

  • the impairment is episodic and from time to time their decision-making capacity is not impaired;
  • his or her capacity for some personal or financial matters is not impaired; or
  • the extent of impairment varies from time to time or depending on the circumstances.

For both Advance Personal Plans and guardianship, a person does not have impaired decision-making capacity just because he or she:

  • has a disability, illness or other medical condition (physical or mental);
  • engages in unconventional behaviour or other forms of personal expression e.g. particular cultural or religious practices, or illegal or immoral conduct;
  • chooses a living environment or lifestyle, or makes decisions others disagree with;
  • does not speak English, or have a particular level of literacy or education;
  • expresses particular religious, political or moral opinion, or sexual preferences;
  • is of a particular sexual orientation or gender identity; or
  • takes or is dependent on alcohol or drugs (or has been). However, the effect of alcohol or drugs may be considered in determining whether the person has impaired decision-making capacity.

For further information about guardians and substitute decision-making visit the Northern Territory Treatment Decisions page.

When consent to treatment is not required

In some circumstances emergency treatment may be carried out without consent. This is discussed further below and on the Northern Territory Treatment Decisions page.

Queensland

Decision-making capacity

An adult is presumed to have decision-making capacity.

A person has decision-making capacity if they:

  • understand the nature and effect of decisions about the matter; and
  • freely and voluntarily make decisions about the matter; and
  • communicate the decisions in some way.

A person has impaired decision-making capacity if they cannot do this. In this case, if a medical treatment decision is required the person’s Advance Health Directive may apply, or, if there is no Directive, their Enduring Power of Attorney. If the person does not have either of those documents, the decision must be made by a substitute decision-maker (e.g. a guardian or statutory health attorney). For further information visit the Queensland Advance Care Directives and Treatment Decisions pages.

An adult must understand the nature and effect of the documents to have capacity to make an Advance Health Directive or Enduring Power of Attorney. Other specific matters which must be understood are listed in the Powers of Attorney Act 1998 (Qld) sections 41 and 42.

The Queensland Government has developed the Queensland Capacity Assessment Guidelines 2020 (effective from 30 November 2020) to provide guidance and general information about capacity, capacity assessment and legal tests of capacity in Queensland. These guidelines are relevant to the Guardianship and Administration Act 2000 (Qld) and the Powers of Attorney Act 1998 (Qld).

When consent to treatment is not required

Generally consent is not required to carry out emergency treatment on a person without capacity. However, it is good clinical practice to obtain a substitute decision-maker’s consent if possible and time permits. This is discussed further below and on the Queensland Treatment Decisions page.

Minor and uncontroversial health care (e.g. a tetanus injection) may also be provided without consent to a person with impaired capacity if:

  • it is necessary to promote the person’s health and wellbeing, and
  • the health provider is not aware of any previous decision about the health care by a substitute decision-maker, or of any dispute about the health care.

However, if the health provider knows, or could reasonably be expected to know, that the person objects to the health care it cannot be provided without consent.

South Australia

Decision-making capacity

A person is presumed to have capacity to make medical treatment decisions.

There are two contexts in which capacity is relevant, and the test for capacity differs in each:

  • capacity for medical treatment decision-making; and
  • capacity relating to guardianship.

Capacity for medical treatment decision-making

A person will have impaired decision-making capacity in relation to a particular medical treatment decision if they cannot:

  • understand information relevant to the treatment decision;
  • retain such information;
  • use such information in the course of making the decision; or
  • communicate their decision in any way.

A person will also have impaired decision-making capacity if they are unable to make a decision about medical treatment because they are comatose or unconscious.

A person:

  • will not be incapable of ‘understanding information’ simply because they can’t understand technical or trivial matters;
  • will not be incapable of ‘retaining information’ merely because they can only do so for a limited time;
  • may fluctuate between having impaired decision-making capacity and full decision-making capacity; and
  • will not have impaired decision-making capacity simply because a decision they make results (or may result) in an adverse outcome.

If a person has impaired decision-making capacity, they may have an Advance Care Directive which provides directions about medical treatment. If they do not have a Directive, a substitute decision-maker may need to make the treatment decision on that person’s behalf. For further information visit the South Australia Advance Care Directives page and Treatment Decisions page.

Capacity relating to guardianship

Where a person has a ‘mental incapacity’ (i.e. they are a ‘mentally incapacitated person’) the South Australian Civil and Administrative Tribunal may make a guardianship order if it believes an order is needed.

‘Mental incapacity’ is defined as the inability of a person to look after their own health, safety or welfare or to manage their own affairs as a result of any:

  • damage to, or any illness, disorder, imperfect or delayed development, impairment or deterioration of the brain or mind; or
  • physical illness or condition that renders the person unable to communicate his or her intentions or wishes in any manner whatsoever.

For further information visit the South Australian Civil and Administrative Tribunal.

When consent to treatment is not required

In some circumstances emergency treatment may be carried out without consent. This is discussed further below and on the South Australia Treatment Decisions page.

Tasmania

Decision-making capacity

A person is presumed to have capacity for medical treatment decision-making.

Whether a person has capacity is relevant to medical treatment decision-making by substitute decision-makers (e.g. the Guardianship Board or a person responsible).

Capacity and medical treatment decision-making by substitute decision-makers

If there is no common law Advance Care Directive, consent must be given either by the person responsible or the Guardianship Board before any medical treatment can be carried out on ‘a person with a disability who is incapable of giving consent’.

A person will have a disability if they have any restriction or lack  of ability to perform an activity in a normal manner, resulting from any absence, loss or abnormality of mental, psychological, physiological or anatomical structure or function.

A person will be ‘incapable of giving consent’ to medical treatment if they cannot:

  • understand the general nature and effect of the proposed treatment; or
  • indicate whether or not they consent or do not consent to the carrying out of the treatment.

For further information about Advance Care Directives and substitute decision-making visit the Tasmania Advance Care Directives and Treatment Decisions pages.

When consent to treatment is not required

Generally consent is not required to carry out emergency treatment on a person without capacity. However, it is good clinical practice to obtain a substitute decision-maker’s consent if possible and time permits (this is discussed further below and on the Tasmania Treatment Decisions page).

Consent is not required in situations where there is no person responsible, the treatment is necessary and will most successfully promote the person’s health and well-being, and the person does not object to the carrying out of the treatment.

However, this does not include medical or dental treatment that involves a substantial risk of death, brain damage, paralysis and other treatment listed in section 12 of the Guardianship and Administration Regulations. In those cases consent must be obtained (from either a person responsible or the Guardianship Board).

Victoria

Decision-making capacity

An adult is presumed to have decision-making capacity unless there is evidence to the contrary. A child under 18 is not presumed to have capacity.

A person (whether an adult or a child) has decision-making capacity if they are able to -

  • understand the information relevant to the decision and its effect;
  • retain that information to the extent necessary to make the decision;
  • use or weigh that information to make the decision;
  • communicate the decision and the person's views and needs about the decision in some way, including by speech, gesture or other means.

A person will understand information relevant to a decision if they can understand an explanation of the information given to the person in a way that is appropriate to the person's circumstances, whether by using modified language, visual aids or any other means.

A person will also have decision-making capacity if they can make a decision with practicable and appropriate support. Examples of this support are using information or formats tailored to the person’s needs, giving a person additional time and discussing the matter with them, and communicating or assisting a person to communicate their decision.

If a person does not have decision-making capacity for medical treatment, a medical treatment decision must be obtained from the person’s Advance Care Directive or medical treatment decision maker, or, in some cases, the Public Advocate.

For further information about adults visit the Victoria Advance Care Directives or Treatment Decisions page. Visit the Children and end of life decision-making page for further information about the law on children in Victoria.

When consent to treatment is not required

Generally consent is not required to carry out emergency treatment on a person without capacity. However, it is good clinical practice to obtain a substitute decision-maker’s consent if possible and time permits. This is discussed further below and on the Victoria Treatment Decisions page.

Where a health professional is unable to locate an Advance Care Directive or a medical treatment decision maker, routine treatment may be given without consent. Routine treatment is any medical treatment other than significant treatment (i.e. treatment that does not involve a significant degree of bodily intrusion, risk, side effects or distress to the person).

Western Australia

Decision-making capacity

A person is presumed to be capable of looking after their own health and safety, and making reasonable judgments in respect of matters relating to them.

A person will no longer have capacity if they are unable to make reasonable judgments in relation to the proposed treatment.

Where this occurs, the person may have an Advance Health Directive containing a decision about the proposed treatment, but if not a substitute decision-maker may need to make the treatment decision. For further information visit the Western Australia Advance Care Directives or Treatment Decisions pages.

When consent to treatment is not required

In some circumstances emergency treatment may be carried out without consent. This is discussed further below and on the Western Australia Treatment Decisions page.

Emergency treatment and consent

Can emergency treatment be provided without consent?

Where a person does not have capacity

Under common law medical treatment can be provided in an emergency to a person who does not have capacity if obtaining consent is not possible and there is an urgent need for treatment e.g. when a person’s life is in danger. The treatment must be necessary to protect the person’s life or health at that time.

Guardianship and medical treatment legislation in most States and Territories generally authorises treatment without consent (i.e. from a person or their substitute decision-maker) if it is needed urgently to:

  • save the person’s life or meet imminent risk to the person’s life;
  • prevent serious damage to health; or
  • prevent significant pain and distress.

In South Australia, Western Australia, and the Northern Territory however, a substitute decision-maker’s consent to emergency treatment must first be sought if it is possible or practicable to do so (e.g. he or she is willing and available to decide).

It is good practice for health professionals in all States and Territories to obtain a substitute decision-maker’s consent if possible. To find out who can be a substitute decision-maker in each State and Territory visit the State and Territory Treatment Decision pages.

Where a person has capacity

Where a person with capacity requires emergency treatment, their consent should be obtained before treatment is provided. Consent to treatment may also be given before an emergency situation arises, for example, in a person’s Advance Care Directive.

Where a person has a mental illness

Where a person with mental illness requires treatment e.g. involuntary treatment in an emergency or other situation State and Territory mental health laws may apply. These laws are outside the scope of this website and are not discussed here.

To learn about the law on when emergency treatment can be provided in each State and Territory visit the State and Territory Treatment Decisions pages.

Can emergency treatment be refused by a person or their substitute decision-maker?

Emergency treatment cannot be provided if it has been lawfully refused. Treatment may be refused:

  • by the person themselves if they have capacity;
  • in a valid Advance Care Directive; or
  • by a substitute decision-maker in accordance with the legislation.

The guardianship and medical treatment legislation in some States and Territories requires a health professional to make reasonable efforts (if practical) to find out whether the person has an Advance Care Directive before giving emergency treatment, or to consider whether the person has previously refused the emergency treatment.

Can life-sustaining treatment be withheld or withdrawn without consent in an emergency?

In all States and Territories except Queensland a clinician can withhold or withdraw futile or non-beneficial treatment without consent in an emergency.

In Queensland, a clinician can only withhold or withdraw life-sustaining treatment in an emergency from a person who does not have capacity if starting or continuing that treatment would be inconsistent with good medical practice, and the person has not objected. This is discussed further on the Queensland Treatment Decisions page.

Key cases

Re B (Adult: Refusal of Medical Treatment) [2002] 2 All ER 449

B suffered a haemorrhage of the spinal column in her neck. After further treatment and relapses, she became paralysed from the neck down and required a ventilator to live. B later requested the ventilator be removed.

The Court noted this case was only about B’s capacity to decide whether the ventilator should be removed. It was not about whether she should live or die, or her best interests. The Court found that B had capacity for the decision. Her capacity was assessed based on her decision-making process and not the outcome of her decision. Underpinning this conclusion was that B could give a clear explanation of her decision-making process, and demonstrated understanding of her condition and its consequences.

Re T (Adult: Refusal of Treatment) [1993] Fam 95

T was 34 weeks pregnant when she was involved in a car accident. Her baby did not survive a subsequent emergency caesarean section. T’s mother was a Jehovah’s Witness and on two occasions after visiting with her mother, T spontaneously advised health professionals that she did not wish to receive blood products. T had assumed that there were other products that would be a satisfactory substitute for blood should a transfusion be necessary. This was not the case, and T needed a blood transfusion to save her life. Her father and partner sought the Court’s approval for a transfusion to be administered on the grounds that T’s capacity was diminished, and that her refusal to consent was invalid due to the overwhelming influence of her mother. The judge authorised the transfusion.

The decision was appealed to a higher court, which found a number of factors had combined to produce a decision to refuse blood products that was not truly T’s. These included the traumatic accident, the death of her child, T’s severe pain and suffering and the influence of medication, as well as the nature of the mother and daughter relationship. On these grounds the Court decided T had not provided a valid refusal of treatment because the refusal was not truly a voluntary expression of T's free will. The Court determined therefore that it was lawful for the hospital to administer the blood transfusion.

Re C (Adult: Refusal of Medical Treatment) [1994] 1 WLR 290

C was serving a prison sentence for attempted murder. While in prison, he was diagnosed with chronic schizophrenia, and was transferred to a secure psychiatric facility. He developed a necrotic leg ulcer so severe that medical advice was to amputate the leg below the knee.

C’s doctors advised he had only a 15% chance of survival without an operation and relying only on conservative treatment. C said he would rather die with two feet than live with one, and refused consent to the amputation. He did agree to more conservative treatment, after which his condition improved and he was no longer at risk of imminent death. C’s solicitor then asked the hospital to agree not to amputate in the future. The hospital would not agree to this so C applied to the Court to prevent the amputation of his leg without his written consent.

The Court said the question was one of capacity to consent to treatment, not the merits of his decision. It found no link between C’s delusions as a result of the schizophrenia and his refusal to undergo the treatment. Although C may not have had capacity for other decisions, in relation to the proposed operation he knew and understood what it involved and the risks of not having it. The Court decided that C could lawfully refuse the amputation of his leg and so the hospital would need his permission if it wanted to operate.

Further resources

Publications

Carmelle Peisah et al, ‘Biggest decision of them all – death and assisted dying: capacity assessment and undue influence screening’ (2019) 49(6) Internal Medicine Journal 792.

Nick O’Neill and Carmelle Peisah, Capacity and the Law (Austlii Communities, 2019).

Sam Boyle, ‘Determining capacity: How beneficence can operate in an autonomy-focused legal regime’ (2018) 26(1) The Elder Law Journal 35-63.

Sam Boyle, ‘Medical evidence of capacity in a legal setting: To what extent do courts and tribunals make their own decisions?’ (2018) 25(2) Journal of Law and Medicine 572-592

Bernadette Richards, ‘General Principles of Consent to Medical Treatment’ in Ben White, Fiona McDonald and Lindy Willmott (eds), Health Law in Australia (Thomson Reuters, 3rd ed, 2018) 135.

Marion Byrne et al, ‘A new tool to assess compliance of mental health laws with the Convention on the Rights of Persons with Disabilities’ (2018) 58 International Journal of Law and Psychiatry 122.

Kelly Purser et al, ‘A therapeutic approach to assessing legal capacity in Australia’ (2015) International Journal of Law and Psychiatry 18-28.

Kelly Purser and Tuly Rosenfeld, ‘Assessing testamentary and decision-making capacity: Approaches and models’ (2015) 23(1) Journal of Law and Medicine 121-136.

Kelly Purser and Tuly Rosenfeld, ‘Evaluation of legal capacity by doctors and lawyers: the need for collaborative assessment’ (2014) 201(8) Medical Journal of Australia 483.

Kelly Purser, Capacity assessment and the law: Problems and solutions (Springer, 2017).