Home Affairs Minister Peter Dutton is standing his ground over stripping Neil Prakash of his Australian citizenship, despite concerns the Islamic State jihadist may be rendered stateless.

Fiji has categorically stated that Prakash is not a citizen, meaning he cannot be stripped of his Australian citizenship.

Fiji's director of immigration, Nemani Vuniwaqa, told The Sydney Morning Herald the island did not allow dual citizenship before 2009 and since Prakash was born in Australia and never applied for Fiji citizenship, he was not a citizen.

To qualify as a Fiji citizen, Prakash would have had to fulfil two conditions: register an application and live in the country for at least three out of the five years before he applied. He had done neither.

"He is not a dual citizen. He has not applied for it," Mr Vuniwaqa said.

But a spokesman for Mr Dutton says the minister made himself clear last week.

"Nothing has changed," the spokesman said on Tuesday.

Legal advice provided to the government about Prakash's citizenship was "very clear", Mr Dutton told reporters in Brisbane last Wednesday.

"Therefore the Citizenship Loss Board, in my judgement, got it right."

Meanwhile, Mr Vuniwaqa says no one from the Australian government spoke to him on the issue.

"I was not even approached by any kind of Australian government official, not by text or SMS message, or email or telephone," he said.

"Nobody goes to my staff except through me."

Melbourne-born Prakash is in jail in Turkey facing terrorism charges.

Under Australian law, the government isn't allowed to revoke an Australian's citizenship if it will leave them stateless.