The High Court in Australia has upheld laws that Papua New Guineans ceased to be Australian citizens when PNG became independent in 1975.
Amos Bode Ame argued in Australia's highest court that he had remained an Australian citizen after his native country became independent and never become a PNG citizen because he did not take steps to renounce his Australian citizenship.
He was born in 1967 in the Southern Highlands when it was administered by Australia and by virtue of this had Australian citizenship.
However Australia's Papua New Guinea Independence Act provided that after Independence Day, Australia ceased to have any sovereignty, sovereign rights or administrative rights in relation to PNG.
The PNG Constitution did not allow dual citizenship and declared that anyone who was born in PNG and had two indigenous grandparents was automatically a PNG citizen.
All four of Mr Ame's grandparents were born in the Southern Highlands.
The High Court unanimously ruled that Mr Ame ceased to be an Australian citizen on Independence Day.
