has been codified under s423 Crimes Act
A person carries out conduct in self-defence if and only if the person believes the conduct is necessary:
- to defend himself or herself or another person, or
- to prevent or terminate the unlawful deprivation of his or her liberty or the liberty of another person, or
- to protect property from unlawful taking, destruction, damage or interference, or
- to prevent criminal trespass to any land or premises or to remove a person committing any such criminal trespass,Once self defence is raised in the evidence, the Crown must satisfy the court that the defendant was not acting in self-defence beyond reasonable doubt: s. 419 Crimes Act. Even if self-defence is raised in the Crown case, the issue may only be determined by the jury: DPP Ref (No. 1) (1992) 60 A Crim R 43. To convict, the jury must be satisfied that:
- Duress: is a defence normally utilised by actors if they were committing the offence under the threat of death or serious bodily harm, as seen in Lynch v DPP .
- Self defence is not available as a defence to murder, when force is used to protect property only or to prevent trespass: s. 420.
- The defence is not limited to situations where death or serious bodily injury is threatened: Honeysett (1987) 34 A Crim R 277. Before self-defence can be left to a jury there must be a threat of immediate harm: PRFN  NSWCCA 230.
- there is no reasonable possibility that the accused did the acts by reason of a threat of death or really serious harm, or
- that there is no reasonable possibility that a person of ordinary firmness (of the age and sex of the accused) would act the way the accused did, or
- the accused failed to take advantage of an opportunity which was reasonably open to him to render it ineffective: Graham  1 All ER 801, Abusafiah (1991) 56 A Crim R 424.
A crucial question in determining whether or not the accused failed to take advantage of an opportunity to render the threat ineffective was whether or not the accused could have contacted the police: Taiapa v The Queen  HCA 53.