10 / 5 / 2022

Self-Defence Laws [ACT]

In ACT, you may be found not guilty of a criminal offence if a court is satisfied that you were carrying out your actions in self-defence. This can be self-defence of yourself, or another. Self-defence is usually raised in offences relating to violence, and includes charges such as murder and resisting arrest.

In a criminal hearing or trial, is up to the person who is charged with a criminal offence, or their legal representative, to raise self-defence. Once it has been raised, it is then up to the prosecution to prove that those actions were not in self-defence. If the court is satisfied that a defendant’s actions were in self-defence, then the court can dismiss the charge.

The law of self-defence in the ACT is governed by both legislation and case law, depending on the type of criminal offence a defendant it alleged to have committed.



For offences that were created after 2003, or have been omitted and remade since 2003, self-defence is legislated in section 42 of the Criminal Code 2002 (ACT) (“the Code”). Examples of offences include:

  • Assault frontline community service provider; and
  • Murder.

Section 42 of the Code states that a person is not criminally responsible for an offence if the person carries out the conduct required for the offence in self-defence.

The section then goes into detail about what conduct and circumstances are necessary to establish self-defence at law.

Subsection 2 states that a person carries out conduct in self-defence only if the person believes the conduct is necessary—

 (i) to defend himself or herself or someone else; or

 (ii) to prevent or end the unlawful imprisonment of himself or herself or someone

else; or

 (iii) to protect property from unlawful appropriation, destruction, damage or interference; or

 (iv) to prevent criminal trespass to land or premises; or

 (v) to remove from land or premises a person committing criminal trespass.

The court then has to consider whether the conduct of the defendant was a reasonable response in the circumstances as the person perceives them.

Section 42 of the Code then goes on to state a number of circumstances where the conduct of a person will not be self-defence. This includes:

If the person uses force that involves the intentional infliction of death or serious harm—

 (i) to protect property; or

 (ii) to prevent criminal trespass; or

 (iii) to remove a person committing criminal trespass; or

 (b) the person is responding to lawful conduct that the person knows is lawful.



For offences that pre-date the implementation of the Code in 2003, and that have not been omitted or remade since that time, the principles of self-defence are derived from case law and have been defined by the High Court in Zecevic v DPP.  An example of an offence that pre-dates the criminal code is Assault occasioning actual bodily harm. The test is similar to the Code but not identical.

The principle in Zecevic asks the court to consider whether the accused believed upon reasonable grounds that it was necessary in self-defence to do what he [or she] did (at [661]).

Essentially, there are two (2) limbs to self-defence at common law. The onus then rests on the prosecution to disprove one (or both) of those limbs:

  1. The accused must have believed at the time that s/he committed the relevant act that what s/he was doing was necessary (known as the “subjective element”); and
  2. That belief must have been based on reasonable grounds (known as the “objective element”).

The first ‘limb’ is a subjective test. This means that it asks the court to consider what the accused person actually believed at the time, not what someone else, or a reasonable person in their situation, believed at the time.

The second ‘limb’ is an objective test. This means that it asks the court to consider whether the belief, in the eyes of a reasonable person, would be considered reasonable.



There are a number of additional considerations that the court may take into account when considering self-defence in both the Code and at common law. These can include:

  • Whether the defendant was intoxicated at the time
    • This may be relevant to the person’s belief in necessity of their actions
  • Whether the alleged victim was using lawful force
    • Self-defence is still available to a defendant in circumstances where the complainant was using lawful force
      • For example: a police officer executing an arrest of the defendant, or acting in their capacity as a police officer
  • Whether the actions were proportionate to the immediate threat as perceived by the defendant
    • For example: where a defendant feared being punched by the victim and responded by stabbing them, it would not be a proportionate response in the circumstances. However, if the alleged victim had attempted to stab the defendant and they responded by stabbing them, it may amount to a defence of self-defence
  • Whether the defendant acted pre-emptively in applying force
    • Self-defence may still be available to a defendant whose actions were carried out pre-emptively, before there was an immediate threat of danger
      • For example: in circumstances of prolonged domestic violence (battered wife syndrome)

Stephanie Beckedahl, Senior Lawyer

[1] (1987) 162 CLR 645.