Citizenship rules may claim Joyce

Deputy Prime Minister Barnaby Joyce may become become the fifth federal politician to be removed from parliament for holding dual citizenship, after New Zealand's prime minister said Mr Joyce was a citizen of that country.

The Nationals leader told parliament today he had been contacted by the New Zealand High Commission last week to advise him that he may be a citizen of NZ by descent.

“Needless to say I was shocked to have received this information. I’ve always been an Australian citizen, born in Tamworth just as my mother (was), and my great grandmother was born there 100 years earlier,” he said.

“Neither I nor my parents have ever had any reason to believe that I may be a citizen of any other country.

“I was born in Australia in 1967 ... I think I am fifth generation.

“My father, who was born in New Zealand, came to Australia in 1947 as a British subject.”

Mr Joyce said based on legal advice from the solicitor-general, the federal government was of the view he has not breached section 44 of the constitution, which bars dual citizens from sitting in parliament.

However, Mr Joyce has asked the government to refer the matter to the High Court.

"Given the strength of the legal advice the government has received, the prime minister has asked that I remain deputy prime minister and continue my ministerial duties," Mr Joyce said in parliament.

Following Mr Joyce's announcement, New Zealand Prime Minister Bill English confirmed the issue, saying unwittingly or not, Mr Joyce was a citizen of NZ.

That was backed by the country's internal affairs minister, Peter Dunne.

Speculation over a number of MPs citizenship has plagued both the House of Representatives and the Senate since Greens MPs Scott Ludlam and Larissa Waters both resigned after discovering they were dual citizens.

Coalition MP Matt Canavan shortly followed after was forced to resign from cabinet amid uncertainty over his Italian dual citizenship.