Australian nationality law determines who is and who is not an Australian

Australian people

Australian people, or simply Australians, are the citizens of Australia. Australia is a multi-ethnic nation, and therefore the term "Australian" is not a racial identifier. Aside from the Indigenous Australian population, nearly all Australians or their ancestors immigrated within the past 230 years...

, and is based primarily on the principle of Jus soli

Jus soli

Jus soli , also known as birthright citizenship, is a right by which nationality or citizenship can be recognized to any individual born in the territory of the related state...

. The status of Australian citizenship was created by the Nationality and Citizenship Act 1948 (later renamed the Australian Citizenship Act 1948) which received Royal Assent on 21 December 1948 and came into force on 26 January 1949. The 1948 legislation has been amended many times, notably in 1973, 1984, 1986 and 2002.