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.

This page explores the law relating to consent to treatment, 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 medical examination.

However, examples of when a person’s consent is not required include when:

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 as part of their decision-making process.

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) (below).

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 based on 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) (below) 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. Indeed, 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 additional specific legislation in your State or Territory, 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 health attorney or guardian.

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 further information about substitute decision-making by health attorneys visit the Australian Capital Territory Stopping Treatment page.

When consent to treatment is not required

Generally emergency treatment may be carried out without consent. This is discussed further on the Australian Capital Territory Stopping Treatment 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 may need to make the treatment decision on that person’s behalf. For further information visit the New South Wales Advance Care Directives page and Stopping Treatment page.

Capacity for appointment of a guardian

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.

When consent to treatment is not required

Generally emergency treatment may be carried out without consent. This is discussed further on the New South Wales Stopping Treatment 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 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 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 Stopping Treatment page.

When consent to treatment is not required

In some circumstances emergency treatment may be carried out without consent. This is discussed further on the Northern Territory Stopping Treatment 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. For further information visit the Queensland Advance Care Directives page and Stopping Treatment page.

Guidance on matters a person needs to understand to have capacity to make an Advance Health Directive or Enduring Power of Attorney are included in the Powers of Attorney Act 1998 (Qld) sections 41 and 42.

When consent to treatment is not required

Generally emergency treatment may be carried out without consent. This is discussed further on the Queensland Stopping Treatment 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 a 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 Stopping Treatment 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
  • any 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 SACAT.

When consent to treatment is not required

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

Tasmania

Decision-making capacity

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

The key context in which capacity is relevant is in relation to medical treatment decision-making by substitute decision-makers.

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 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.

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

For further information about Advance Care Directives and substitute decision-making visit the Tasmanian Advance Care Directives page and Stopping Treatment page.

When consent to treatment is not required

Generally, treatment may be carried out without consent if:

  • there is no person responsible, the treatment is necessary to 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

A person is presumed to have decision-making capacity unless there is evidence to the contrary.

A person has decision-making capacity if they are able to—

  • understand the information relevant to the decision and the effect of the decision;
  • retain that information to the extent necessary to make the decision;
  • use or weigh that information as part of the process of making the decision;
  • communicate the decision and the person's views and needs about the decision in some way, including by speech, gestures 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 it is possible for the person to 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 visit the Victoria Advance Care Directives page or Stopping Treatment page.

When consent to treatment is not required

Generally emergency treatment may be carried out without consent.This is discussed further on the Victoria Stopping Treatment 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 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 page or Stopping Treatment page.

When consent to treatment is not required

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

Key cases

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 consent, and that it was lawful for the hospital to administer the blood transfusion.

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 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 have lacked 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

Richards B. General principles of consent to medical treatment. In: White B, McDonald F, Willmott L, editors. Health Law in Australia. 3rd ed. Sydney: Thomson Reuters, 2018.

Byrne, M, White, B, McDonald, F. A new tool to assess compliance of mental health laws with the Convention on the Rights of Persons with Disabilities. International Journal of Law and Psychiatry 2018; 58: 122-142.

Purser, K, Rosenfeld, T. Evaluation of legal capacity by doctors and lawyers: the need for collaborative assessment. Med J Aust 2014; 201(8): 483-485.

Guidelines

Medical Board of Australia. Good Medical Practice: A Code of Conduct for Doctors in Australia. 2014: 3.5, 3.8.