In July 2003, the Rann Government (SA) introduced laws allowing householders to use "whatever force they deem necessary" when confronted with a home invader.
Householders who kill or injure a home invader escape prosecution provided they can prove they had a genuine belief that it was necessary to do so to protect themselves or their family.
[10] The law was strongly opposed by then-Director of Public Prosecutions Paul Rofe, QC, and lawyer Marie Shaw, who is now a District Court Judge.
In the High Court case of Viro v The Queen,[1] Aickin J said: The defence was first recognised in the common law in R v McKay,[12] where a farmer shot and fatally wounded a chicken thief, and confirmed in R v Howe where Mayo J held at 121-122: This mitigatory defence was abolished in Zecevic v Director of Public Prosecutions[2] which expressed the view that provocation should be the alternative considered.
Unlike South Australian law, s420 of the NSW Crimes Act explicitly states that self-defence is not available as a defence to murder if death is inflicted to prevent criminal trespass.