Commonly, if you were born overseas on or after 26 January 1949 to an Australian citizen parent, you may be eligible to apply for Australian citizenship by descent.
If your responsible parent became an Australian citizen by descent, he or she must have been present in Australia for periods totalling two years at some time in their life.
If you were born outside Australia or New Guinea before 26 January 1949 you may also be eligible for Australian citizenship by descent if at least one of your responsible parents became an Australian citizen on 26 January 1949.