Last updated 1 February 2023

Before a person can consent to or refuse particular medical treatment, they need to have a reasonable understanding of what that treatment involves. In a medical context, this is often referred to as ‘capacity’ or ‘competency’. This means having the ability to understand the actual treatment information being provided and acting on that information.

To have adequacy competency (see re C [1994] 1 All ER 819 (QBD) – Justice Thorpe) a patient needs to be able to follow these processes:

  • understand and remember treatment information
  • believe the information
  • use the information to arrive a choice about the treatment
  • communicate the decision.

Consent that is obtained through fraud or misrepresentation is not ‘real’ consent. This means that if the information is received in a manner that is unclear or misleading or from someone without appropriate qualifications to provide the information the patient is not properly informed to provide consent.

Types of consent

Where consent is provided to medical treatment by a person, it must be freely given (Beausoleil v Sisters of Charity (1964) 53 DLR 65). The consent provided can either be:

  • express – for example, an individual signs a form consenting to a particular surgical procedure
  • implied – for example, by the actions of the individual attending at a pathology centre, handing over the collection request form and presenting an arm for a blood test, or an individual attending at a pharmacy to have a prescription filled and then taking the medication the doctor has prescribed.

Who can provide consent

Depending on the situation, consent can be given by the patient, their parent/guardian, the courts or a substitute decision maker.


There is a general presumption that an adult has capacity to make their own medical decisions (MB [1997] SCR 514 at 513) (s 11 Guardianship and Administration Act 2000 (Qld)) (Guardianship and Administration Act). A person who is 18 years of age or older and competent can consent or refuse to consent to medical treatment. As outlined above, a person making such a decision must be able to understand the relevant medical condition and the choices available in relation to the treatment of the condition. If consent to treatment is provided by a competent patient, the treatment provided is lawful.

A person over 18 years of age may not be able to consent to medical treatment if they have impaired decision-making capacity. Impaired decision-making capacity can be due to a range of reasons and can be ongoing, intermittent or temporary. Examples of impairment include:

  • medical conditions that significantly impair cognitive function or the ability to communicate such as dementia, advanced multiple sclerosis, intellectual impairment and some mental illnesses
  • medical treatment such as being in an induced coma or under general anaesthesia
  • traumatic injuries such as an acquired brain injury.

Whether these conditions are temporary or permanent, it is important to understand the wide range of reasons why an adult person may be incapable of providing consent.


Unlike adults, children under the age of 18 are presumed not to have capacity to make their own medical decisions, and this responsibility usually falls to the child’s parent or guardian. This is not, however, a blanket rule.

A child under 18 may be able to make their own medical decisions where they have sufficient understanding and intelligence to fully understand the treatment (see Gillick v West Norfolk and Wisbech Area Health Authority [1986] AC 112 and Secretary, Department of Health and Community Services v JWB and SMB (Marion’s Case) (1992) 175 CLR 218). A variety of factors can impact on any assessment of the capacity of a child to provide consent to medical treatment including their age and individual maturity, and the complexity of the medical treatment being consented to.

The ability for a parent to consent to their child’s treatment is also limited. In Marion’s Case, the High Court of Australia said that a parent can only consent to procedures that are in the child’s best interest, and there are some special medical procedures that will require a court’s consent. These ‘special medical procedures’ may include, but are not limited to:

Queensland Health’s ‘Guide to Informed Decision-making in Healthcare’ provides more information at section 3.1.1 about the overlap between a child’s and parent’s authority to provide consent. For further details on medical treatment and children see the Queensland Law Handbook chapter ‘Parents, Children and the Law’.


The Supreme Court can assist in cases involving incapacitated individuals or minors and medical treatment. The Supreme Court has the power to protect the person and property of those who are unable to look after themselves, and it covers both adults lacking capacity and children. An application needs to be made to the Supreme Court, and the court has broad powers such as:

The Federal Circuit and Family Court of Australia can also withhold or grant consent to medical treatment for a child relying on its welfare jurisdiction in the Family Law Act 1975 (Cth). These powers are applicable in cases where:

  • separated or divorced parents cannot agree on treatment (e.g. vaccinations; see Makinen v Taube [2021] FCCA 1878)
  • the parents and the child do not agree about medical treatment
  • the treating doctor does not agree with the decision made by the parents and/or the child concerning the treatment.

Any decision made by a court must put the best interests of the incapacitated person or the child first.

Substitute decision makers

Legislation establishes a substitute decision-making framework whereby decisions are made on behalf of an individual lacking capacity. Applying this legislation, a person over the age of 18 years may, while they still have capacity, prepare for any future incapacity and healthcare decision making under the Powers of Attorney Act 1998 (Qld) (Powers of Attorney Act) by preparing an:

  • Advance Health Directive (ss 35, 36 Powers of Attorney Act)
  • Enduring Power of Attorney appointing an attorney who is authorised to make decisions in relation to the healthcare of the individual (s 32 Powers of Attorney Act).

These documents can be complex and legal advice should be sought on an individual’s unique circumstances to ensure that the written documents reflect the person’s wishes.

Advance health directives

An advance health directive is a document that allows an individual to make known their wishes regarding their future medical treatment. Under the Powers of Attorney Act, some key features of the directive include:

  • it only operates if the individual has impaired capacity in relation to healthcare treatment (s 36 Powers of Attorney Act)
  • it can direct the withholding or withdrawal of a life-sustaining measure in certain situations (s36(2) Powers of Attorney Act)
  • it cannot be used to authorise, justify or as an excuse for euthanasia (s 37 Powers of Attorney Act)
  • it can direct that a person (an attorney) be appointed to make decisions about a health matter if the advance directive is inadequate (s 35(1)(c))
  • an individual can make directions in relation to a special health matter, including the removal of tissue from an adult while alive for donation, sterilisation, termination of pregnancy, participation in special medical research or experimental healthcare (sch 2 ss 6–7 Powers of Attorney Act).

Where the individual does not have an advance health directive and there is no other authorised entity, the Queensland Civil and Administrative Tribunal can provide consent for special healthcare other than electroconvulsive therapy or psychotherapy (s 68 Guardianship and Administration Act).

Enduring power of attorney

An enduring power of attorney provides a broader authorisation for a substitute decision maker to act in relation to financial or personal matters for the person lacking capacity. A personal matter includes health matters but does not include special health matters, which have been explained above (s 32 of Powers of Attorney Act). This document, and the authority contained within it, will only be recognised in Queensland if was prepared in Australia or New Zealand. Outside of these jurisdictions, Queensland does not recognise foreign enduring powers of attorney as valid.

Consent in an emergency

In cases of emergency or necessity, it may not be possible to obtain the consent of an individual to treatment. It may also not be possible to provide full advice about the treatment before it is performed.

In some circumstances, a patient’s consent for one procedure may be extended to cover additional treatment if there is an unforeseen emergency. For example, if a patient having a hernia repair was found to have an infected testicle which was at risk of serious infection if not removed immediately, that would constitute an emergency (see Marshall v Curry [1933] 3 DLR 260). If, however, a patient having a c-section then had a sterilisation procedure performed without any immediate risk, that would not amount to an emergency as the patient could have provided consent later and returned for the procedure (see Murray v McMurchy [1942] 2 DLR 442).

When a person is unable to provide consent, consent can be provided by a person’s health attorney, who may have been appointed by statute or an enduring power of attorney, or by an advance health directive. For example, if you have an advance health directive stating that you do not wish life-sustaining treatment measures in emergency circumstances, such as CPR or assisted ventilation, this will apply in the appropriate circumstances. For more information see the Queensland Law Handbook chapter on ‘Laws Relating to Individual Decision Making’.

Medical treatment without consent

Consent is the key that ‘unlocks the door to treatment’ making a doctor’s action lawful but not obligatory. This means that whilst a patient who has capacity can consent to treatment, they do not have to proceed with the treatment if they do not wish. If none of the exceptions referred to above apply to a situation and medical treatment is received without consent, there are two potential avenues for a claim for damages:

  • battery
  • medical negligence arising out of a failure to warn.

Assault and battery

In Queensland, any physical contact with another person is generally unlawful unless the recipient has consented to that contact. Very few, if any, medical procedures can be performed without touching a patient. For this reason, consent is the essential factor that distinguishes appropriate treatment from an assault or, as it is known at law, ‘battery’.

To provide valid consent to medical treatment, there must be freedom of the will (see Beausoleil v Sisters of Charity (1964) 53 DLR 65), information must be provided in broad terms as to the nature of the procedure (see Chatterton v Gerson [1981] QB 432) and the person must have capacity to give the consent. If treatment is provided without consent, excluding emergencies, the treating health practitioner or health service provider may be liable for assault in a criminal context or battery in a civil context.

It is important to investigate whether consent was obtained prior to treatment and, if not, the patient may have a claim for battery regardless of whether they can prove damage was sustained. This is distinct from other claims for medical negligence and means that the patient is not required to establish loss or damage to be entitled to compensation.

Failure to warn of a material risk

To obtain informed consent, the treating practitioner must provide a proper explanation of the medical treatment and risks associated with the treatment. While this does not mean that a health professional must list every risk associated with the treatment, they do have a duty to warn a patient of a ‘material risk’ (see Rogers v Whittaker (1992) 175 CLR 479).

A risk is material if:

  • a reasonable person in the patient’s position, if warned of the risk, would be likely to attach significance to it
  • the health practitioner is, or should be, aware that the particular patient would be likely to attach significance to the risk.

There are certain circumstances where a health professional is justified in withholding information, such as when the information causing more harm than good to the patient’s physical or mental health.

If a patient brings a claim for failure to warn of a material risk, they must prove that:

  • the health practitioner did not advise them of the risk that eventuated
  • due to the risk materialising, the patient suffered an injury
  • if the patient was aware of the risk before the treatment, they would not have proceeded.

In this type of claim, an expert report commenting on the doctor’s failure is not required, however, a claimant will require evidence that they would not have proceeded with surgery at the time had they been warned of the risk. Their own evidence given after the treatment and with the benefit of hindsight will not be sufficient.