New Zealand authorities have confirmed Deputy Prime Minister Barnaby Joyce is a citizen of their country.

Mr Joyce told parliament on Monday the New Zealand High Commission had contacted him last Thursday with the "shocking" information.

He has referred himself to the High Court after making the stunning announcement stunning announcement.

"On the basis of preliminary advice from their department of internal affairs - which had received inquiries from the New Zealand Labor Party - they considered I may be a citizen by descent of New Zealand," Mr Joyce said.

Mr Joyce made the announcement on Monday. Source: Channel 7

But New Zealand’s Internal Affairs Minister Peter Dunne has confirmed Mr Joyce is a citizen of New Zealand.

According to Sky News The New Zealand High Commission contacted the Deputy PM on Thursday to tell him he could be a citizen by descent through his father.

Mr Dunne told reporters on Monday that Crown Law had checked and Mr Joyce was a citizen under the Citizenship Act of 1948.

Mr Joyce's father was born in New Zealand and came to Australia in 1947 as a British subject - a year before NZ citizenship was created as a legal concept.

"Neither my parents nor I have ever applied to register me as a New Zealand citizen," he said.

"The New Zealand government has no register recognising me as a New Zealand citizen."

The government has received legal advice from the solicitor-general which suggests Mr Joyce would not be found to be disqualified under section 44 of the constitution and would not have to resign as the Member for New England.

More to follow.