Home Affairs Minister Peter Dutton has defended his declaration that Islamic State extremist Neil Prakash has been stripped of his citizenship.

Key points: A government board was satisfied Neil Prakash held dual citizenship

A government board was satisfied Neil Prakash held dual citizenship That paved the way for him to be stripped of his Australian citizenship

That paved the way for him to be stripped of his Australian citizenship But Fiji's Government says the Islamic State extremist was never a Fijian citizen

On Saturday Mr Dutton announced Prakash was the 12th dual citizen to lose Australian citizenship for engaging in terrorism.

Terrorists who only hold Australian citizenship cannot lose it, because doing so would leave them stateless.

Prakash, 27, was born to a Fijian father and Cambodian mother.

But the head of Fiji's Immigration Department, Nemani Vuniwaqa, told a local newspaper Prakash was not a Fijian citizen.

"Neil Prakash has not been or is a Fijian citizen," Mr Vuniwaqa told the Fiji Sun.

"For a child of a Fiji citizen born overseas, the parent has to apply for citizenship for the child to become a Fiji citizen. The department has searched the immigration system and confirms that he has not entered the country nor applied for citizenship since birth."

Dutton says loss of citizenship was automatic

Mr Dutton said a government board "carefully considered" the case and was satisfied that Prakash held another citizenship.

Who is Neil Prakash? Neil Prakash, 27, is of Fijian-Indian and Cambodian background, and attended Melbourne's controversial Al-Furqan Islamic Centre after converting

Neil Prakash, 27, is of Fijian-Indian and Cambodian background, and attended Melbourne's controversial Al-Furqan Islamic Centre after converting He is believed to have left for Syria in 2013, where he changed his name to Abu Khaled al-Cambodi and was put on a US kill list

He is believed to have left for Syria in 2013, where he changed his name to Abu Khaled al-Cambodi and was put on a US kill list Prakash was linked to several Australian-based attack plans and calls for lone-wolf attacks against the US

Prakash was linked to several Australian-based attack plans and calls for lone-wolf attacks against the US He has also appeared in IS propaganda

He has also appeared in IS propaganda Paul Maley, the national security editor of The Australian newspaper, said Prakash was "a lonely lost sort of a guy, he was a gang member, he had a problem with drugs, he was a failed hip hop artist"

"Absolutely the letter of the law has been followed here," he said.

"The Citizenship Loss Board, comprising senior officials from several government departments, law enforcement and security agencies, examined the requirements for cessation of Australian citizenship.

"Neither the Citizenship Loss Board nor I make decisions on whether an individual ceases to be an Australian citizen. The provisions operate automatically by virtue of a person's conduct.

Mr Dutton said he was not aware of any dispute with Fiji over stripping the terrorist of his citizenship.

"The Government has been in close contact with the Government of Fiji since Mr Prakash was determined to have lost his citizenship," he said.

Prakash is currently in jail in Turkey, where he faces multiple charges related to being a member of the Islamic State (IS) group.

The Government has previously attempted to extradite him to Australia.

"Prakash is rotting in a jail at the moment and I hope he's there for a long period of time to come," Mr Dutton said.

According to senior counter-terrorism officials, Prakash was a pivotal figure inspiring and encouraging terrorist plots in Australia.

He appeared in IS propaganda urging attacks in Australia and has been linked by the FBI to a failed plot to attack the Statue of Liberty in New York.

Mr Dutton said there would be an appeal process for Prakash, but that the Australian Government would allege that he had "essentially self-renounced, through his actions, his Australian citizenship".