Section 418 of the Crimes Act of 1900 provides that you are not criminally responsible for an offence in New South Wales if:
1. You believed your conduct was necessary to:
(a) Defend yourself or another person,
(b) Prevent the unlawful deprivation of your liberty or that of another person,
(c) Protect your property from being taken, destroyed, damaged or interfered with, or
(d) Prevent criminal trespass to your land, or remove a person from criminally trespassing, and
2. Your conduct was a reasonable response in the circumstances as you perceived them.
Self-defence is not available where you used force that led to the reckless or intentional infliction of death in circumstances where your conduct was solely to protect property or remove a criminal trespass.