If you were born in Australia before 20 August 1986, when you apply for an Australian passport you will need to provide proof of your Australian citizenship. You will need to provide your full birth certificate issued by an Australian Registry of Births, Deaths and Marriages (RBDM) to the Australian Passport Office (APO).
If your parents were in Australia as diplomats or consular officers at the time of your birth, you might need to provide a citizenship certificate as evidence that you are an Australian citizen. You will need to lodge
Form 119 Application for evidence of Australian citizenship (445KB PDF).