Lawful Excuse

This defence is available in circumstances where a person comes into physical contact with another person (sometimes causing pain), but there has been agreement to the physical contact, such as when a doctor or dentist is treating a patient or when a person is playing sport.

If however the accused was playing sport and made contact outside the rules of the sport and that resulted in the other player being injured, then this may constitute assault. The same applies to a medical practitioner.
Consent Defence

Actions that may otherwise constitute an assault at law will not constitute an assault if there was consent by the alleged complainant, such as in the sport of boxing for example. The consent defence may also be arguable where two people are engaging in a fair fight or where a person agrees to be hit in a consensual context, such as a sexual relationship.

This defence does not apply in unlawful situations or in situations where the degree of harm suffered is severe (such as a broken bone or significant burning).

Lawful Chastisement Defence

In 2000 section 61AA was added to the Crimes Act 1900. This provision sets out what is lawful when physically punishing a child. The section provides that the level of force used must be reasonable and must not be to the child’s head or neck and must only last for a short time.


This defence is outlined in section 418 of the Crimes Act 1900.

It is a defence to an assault charge if the accused believed that their actions were necessary to defend either themselves or another person or to prevent the unlawful deprivation of liberty or to prevent or stop a criminal trespass.

The action or actions that the accused took must have been reasonable in the circumstances as they understand them. If self-defence is raised by the accused, then the prosecution must prove that the accused’s actions were not a reasonable response to the circumstances as he or she perceived them. If the prosecution does not establish this the accused will be acquitted from the charges.


The defence of intoxication does not apply to most assault offences.

It only applies to offences that are set out in section 428B of the Crimes Act 1900, such as maliciously inflict grievous bodily harm with intent. When dealing with this offence the court may take into account the level of intoxication of the accused when deciding whether the prosecution have established that the accused formed the intention to bring about a specific result. Intoxication is not a defence if the accused became intoxicated in order to help them commit the offence.