Defence of Self-Defence

This page deals with the criminal defence of self-defence, which can be invoked by an accused person who uses force in response to a perceived threat of harm. Self-defence allows an accused person to assert that their actions were warranted because they were protecting themselves, another person, or property from harm. The law recognises that a person cannot be expected to remain passive when faced with a threat of unlawful harm.


Self-defence in defined different in the legislation on different states and territories. The relevant provisions are as follows:

In Australia, the 1987 High Court ruling of Zecevic v The Queen is the leading case on the subject.

What is required for self-defence to succeed?

For an accused person to successfully rely on self-defence, they must satisfy the following criteria:

• They held a genuine belief, based on reasonable grounds, that it was necessary to use force to protect themselves or another person from impending unlawful harm.

 • The level of force was proportionate to the perceived threat.

 • Their belief and their use of force were based on reasonable grounds. This means that the accused person’s conduct was reasonably justifiable given the situation as they perceived it.

Burden of proof

Although the defence is responsible for raising self-defence, the prosecution then assumes the burden of disproving any of the elements beyond a reasonable doubt. If the prosecution cannot demonstrate beyond a reasonable doubt that the accused did not act in self-defence, the accused will be acquitted of the offence.

When can self-defence not be used?

It is important to keep in mind that the defence of self-defence cannot be relied on if the accused person instigated the altercation or used excessive force in response to the threat that they perceived. If the accused person used excessive force – such as fatally injuring an attacker in response to a non-lethal attack or causing severe harm in defence of property – self-defence does not provide a defence.

Zecevic v DPP

The leading legal authority on the defence of self-defence in Australia is the High Court‘s decision in Zecevic v Director of Public Prosecutions (1987). The case revolved around the accused killing his neighbour and claiming he acted in self-defence. The accused maintained that he felt compelled to act due to his belief that the victim was armed with a knife and shotgun, which led him to retrieve his own gun and shoot the man.

The court in that case established the following test for assessing 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.’

Effect of self-defence

A person who commits an act in self-defence is not guilty of a criminal offence. A person who successfully relies on the defence of self-defence will receive a full acquittal.

If you require legal advice or representation in any legal matter, please contact Go To Court Lawyers. 


Fernanda Dahlstrom

Fernanda Dahlstrom has a Bachelor of Laws from Latrobe University, a Graduate Diploma in Legal Practice from the College of Law, a Bachelor of Arts from the University of Melbourne and a Master of Arts (Writing and Literature) from Deakin University. Fernanda practised law for eight years, working in criminal defence, child protection and domestic violence law in the Northern Territory. She also practised in family law after moving to Brisbane in 2016.
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