Adopted by a Queensland family at the age of six and later granted an Australian passport, Edward McHugh never thought he was anything but Australian.

But the 50-year-old, who was born in the Cook Islands, now faces deportation and being torn apart from his seven children, after the Australian government revoked his passport and told him he was in fact never a citizen.

“I grew up in Toowoomba, Mum and Dad are both Aussies, they never thought they had to do anything for me [to be a citizen] ... I thought I was Australian,” McHugh told SBS News.

“It is quite baffling, I was Australian until they wanted to kick me out,” he said.

He is challenging the deportation order.

The Department of Home Affairs told McHugh this year that he had never applied for citizenship by descent and that his adoption did not make him an Australian citizen because it happened before the law was changed.

“Your Queensland birth certificate [granted in retrospect after his adoption] sets out that the date of registration is 4 November 1976. Automatic acquisition visa adoption did not come into effect until 22 November 1984, therefore you did not automatically become an Australian citizen via adoption,” a letter from the department reads.