Before 1788, laws were passed down by word of mouth within the many different Aboriginal and Torres Strait Islander tribal groups. These laws could take the form of customs, taboos, traditions and rites, as they still do. When the British arrived, they declared Australia terra nullius (land of no one) and imposed British laws (terra nullius was finally overturned by the High Court's Mabo judgment in 1992 : see 'Native title' under 'Land and its uses').
After 1788, British governors governed the six Australian colonies using British laws. Gradually, the colonies were allowed to govern themselves and pass their own laws. However, any Australian law that conflicted with a British law was void. This was true for federal laws until 1939 and state laws until 1986 (when the Australia Act 1986 came into force).
In 1901 the six colonies joined to become the six states of Australia. The new federal parliament later legislated for the Australian Capital Territory and the Northern Territory, providing for representative governments in those territories.
The federal parliament could pass laws in areas set out in the constitution; all other areas were left to state governments. The constitution gives and limits power, and sets out the features of our system of government, which is sometimes called the Westminster system because of its English origins.