Australia's attempt to strip citizenship from an alleged...

Australia's attempt to strip citizenship from an alleged recruiter for Islamic State has been thrown into doubt after Fiji reportedly said he was not one of its citizens.

Home Affairs Minister Peter Dutton said on Saturday that the country was much safer after the government revoked Neil Prakash's Australian citizenship.

Canberra believes Prakash -- who is wanted over an alleged plot to behead a Melbourne police officer -- is a dual national as his father was Fijian.

A person with such dual status can be stripped of their Australian citizenship if they engage in terrorism-related conduct, and Islamic State was declared a terrorist organisation in 2016 for this purpose.

The government cannot revoke single Australian citizenship as that would leave a person stateless.

However, Fiji's Immigration Department director Nemani Vuniwaqa said Prakash was not one of its citizens, the Fiji Sun newspaper reported on Tuesday.

"Neil Prakash has not been or is a Fijian citizen. He was born in Australia and has acquired Australian citizenship since birth," he was quoted as saying.

"The Department has searched the Immigration system and confirms that he has not entered the country nor applied for citizenship since birth."

If Prakash does not hold dual status, the way could potentially be opened for a legal challenge against the Australian government as he may be legally entitled to retain his citizenship.

The Home Affairs Department on Tuesday was unable to officially confirm whether or not Prakash was a Fijian citizen.

"A person may only lose their Australian citizenship under the Australian Citizenship Act 2007 if they are a national or citizen of a country other than Australia," a departmental spokesperson said via email.

"Australia is committed to upholding our international legal obligations, including our obligation not to render a person stateless."

Prakash has been in Turkey on trial for charges relating to being a member of Islamic State since being caught there in October 2016 after leaving Islamic State-controlled territory.

Canberra is seeking his extradition pending the outcome of his trial and any jail term he serves in Turkey. If later convicted in Australia, he would also serve time there.