Self-defence in Australia: What does the law say?


Fortunately, criminal assaults are not commonly issues for most people. Less fortunately, it is a fact of life that a situation may arise where another party attempts to inflict personal harm or injure property. Criminal law in Australia recognises this, and affords a narrow window to allow for preservation of either the self or the property.

The general rule of self-defence

As a rule, an individual can take any defensive or evasive steps they believe to be reasonably necessary given the situation. Unlike much of the common law, self-defence is not a formulaic area of law, but concerns itself with the circumstances of each instance.

Zecevic v DPP (1987) 162 CLR 645 provides the leading authority on self-defence, and involved the accused killing his neighbour following an argument. The accused believed that the deceased had a knife and gun, leading the accused to retrieve his gun and shoot his neighbour dead.

During the trial, the judge withdrew the issue of self-defence, so Zecevic was convicted. On appeal to the High Court, a retrial was ordered with Dawson and Toohey JJ setting out the definitive requirements for self-defence:

“The question to be asked in the end is quite simple. It is whether the accused believed upon reasonable grounds that it was necessary in self-defence to do what he did. If he had that belief and there were reasonable grounds for it, or if the jury is left in reasonable doubt about the matter, then he is entitled to an acquittal. Stated in this form, the question is one of general application and is not limited to cases of homicide.”

Section 10.4(2) of the Criminal Code 1994 (Cth) codifies self-defence requirements, being:

A person carries out conduct in self-defence if, and only if, he or she believes the conduct is necessary:

  • to defend himself or herself or another person; or
  • to prevent or terminate the unlawful imprisonment of himself or herself or another person; or
  • to protect property from unlawful appropriation, destruction, damage or interference; or
  • to prevent criminal trespass to any land or premises; or
  • to remove from any land or premises a person who is committing criminal trespass.

Can self-defence be used in the defence of another person?

While term ‘self-defence’ suggests it is only available when the person is under threat themselves, it can in fact also be used in the defence of another. At common law, self-defence was traditionally limited to certain relationships – parent and child, husband and wife or ‘master and servant’. However, numerous Australian jurisdictions allow for self-defence beyond these limited categories, as codified in s 418(2)(a) of the Crimes Act 1900 (NSW) and s 9AC, s9AE(a) of the Crimes Act 1958 (VIC).

Self-defence and the protection of property

Self-defence as a principle is available for acts in defence of property. However, use of lethal force is probably not justified under the test that Dawson and Toohey established in Zecevic. In that case, the High Court found that the only justification for the use of lethal force is under circumstances where the threat was such that the person held a reasonable apprehension that death or serious harm may be the result of the attack.

Legislation that refers to use of force in defending of property, such as s 267 and s 274-278 of the Criminal Code 1899 (QLD) ,states that any use of force in the defence of property must be both reasonable and necessary. As such, force resulting in death or grievous bodily harm is largely prohibited. Please note that this is only a very general guide to the laws of self-defence in Australia, and does not purport to comprehensively address the issue. Please seek legal counsel, should you require it.