Adult applicants who acquired the citizenship or nationality of another country by doing any act or thing other than marriage before 4 April 2002 automatically lost their Australian citizenship. Their children under 18 years also lost their Australian citizenship unless the other parent was also an Australian citizen or permanent resident. People in this situation should be referred to DIAC to determine their citizenship status and to inquire about resumption of their Australian citizenship if necessary.

From 4 April 2002 acquiring the citizenship or nationality of another country does not result in the loss of Australian citizenship. However this is not retrospective and persons who acquired another citizenship prior to this date may have lost their Australian citizenship.

Passport application forms include a declaration regarding citizenship. Applicants who sign the declaration and meet all other criteria do not need to provide proof that they have not acquired citizenship or nationality of another country.

All citizenship enquiries must be referred to the Citizenship Section of DIAC for resolution before any document is issued.