Four members of Australia's federal parliament have revealed possible second citizenships that make them ineligible for office. Barnaby Joyce has been referred to the High Court for investigation of the matter.
The deputy prime minster of Australia, Barnaby Joyce, revealed on Monday that he could be ineligible to hold office as he may hold New Zealand citizenship.
He told lawmakers that he had referred himself to the country's High Court and would retain his position while it investigates.
Joyce said that he had received legal advice that he had not breached the Constitution.
Public broadcaster ABC said it had received confirmation from the New Zealand government that Barnaby Joyce did hold citizenship.
If he does step down his would be the fourth political scalp claimed in a spate of revelations about dual nationalities in Australian federal politics.
Last month Australian Resources Minister Matt Canavan stepped down after his mother revealed that he might also hold Italian citizenship. This was an embarrassing move for the ruling coalition as they had earlier savaged the minor Greens party when two of its senior members were forced to step down given dual nationality.
Joyce had taken over Canavan's cabinet responsibilities as the High Court investigated the matter.
Single nationality rule
Australian law prohibits lawmakers from holding citizenship of a "foreign power" including fellow Commonwealth states, even on a dual-nationality basis. The rule is seen by many as arcane considering that it precludes a quarter of the nation from joining parliament.
Green Senators Scott Ludlam and Larissa Waters resigned in quick succession after the bombshell announcements that one held New Zealand citizenship and the other Canadian citizenship.
Ludlam, the first of the recent group to fall foul of law, gave Barnaby Joyce the traditional Maori greeting in a tongue-in-cheek post on Twitter.
There were widespread calls from the opposition for Joyce to step aside, threatening the government's one-seat majority in the lower house of parliament.
Joyce is well known for forcing Hollywood actor Johnny Depp and his then-wife Amber Heard to film an apology video for bringing their pet dogs into Australia.