Australian legal system

The legal system of Australia has multiple forms. It includes a written constitution, unwritten constitutional conventions, statutes, regulations, and the judicially determined common law system. Its legal institutions and traditions are substantially derived from that of the English legal system, which superseded Indigenous Australian customary law during colonisation. Australia is a common-law jurisdiction, its court system having originated in the common law system of English law. The country's common law is the same across the states and territories.

The Australian Constitution sets out a federal system of government. There exists a national legislature, with a power to pass laws of overriding force on a number of express topics. The states are separate jurisdictions with their own system of courts and parliaments, and are vested with plenary power. Some Australian territories such as the Northern Territory and the Australian Capital Territory have been granted a regional legislature by the Commonwealth.

The High Court is Australia's apex court. It has the final say on the judicial determination of all legal matters. It hears appeals from all other courts in the country, and is vested with original jurisdiction.

Prior to colonisation, the only systems of law to exist in Australia were the varied systems of customary law belonging to Indigenous Australians. Indigenous systems of law were deliberately ignored by the colonial legal system, and in the post-colonial era have only been recognised as legally important by Australian courts to a limited degree.

Indigenous Australian customary law varied between language groups, clans, and regions. It developed over time from accepted norms within indigenous societies. The laws regulated human behaviour and relationships, mandated sanctions for misdeeds, and connected people with the land and each other through a system of relationships.

Such law is often intertwined with cultural customs, stories, and practices. These customs were and are passed on intergenerationally through oral tradition, often incorporated within cultural works such as songlines, stories and dance.

The laws of England had evolved over centuries, with the common law emerging following the 1200s. This law was introduced to Australia through the colonisation of Australia by the British. By 1824, a court system based on the English model had been established through Acts of the British Parliament. The New South Wales Act 1823 provided for the establishment of a Supreme Court with the power to deal with all criminal and civil matters "as fully and amply as Her Majesty's Court of King's Bench, Common Pleas and Exchequer at Westminster". Inferior courts were also established, including courts of General or Quarter Sessions, and Courts of Requests.

Despite the presence of indigenous inhabitants, Australia was determined to be "settled" rather than "conquered" and as a result all English law "applicable to the new situation and condition of the infant colony" applied, as opposed to the continuation of indigenous laws. This was confirmed by the Australian Courts Act 1828 an act of the Imperial Parliament which had the effect of ensuring that all English common and statute law up to 28 July 1828 was to have effect in New South Wales and Tasmania, and later Victoria and Queensland when they separated from New South Wales. The reception of English law in Western Australia and South Australia was later deemed by statute to have occurred on 1 June 1829 and 28 December 1836 respectively.