Australia’s deputy prime minister has been removed from office by a court because he held New Zealand citizenship when he was elected.

The country’s High Court ruled Barnaby Joyce was ineligible to be elected to parliament in 2016, as the constitution forbids dual citizens from holding office.

Joyce’s father was born in New Zealand and, while he never sought its citizenship, the country has claimed him as a citizen and the High Court ruled on Friday he had been ineligible for election when he stood for the lower house of Australia’s parliament.

The decision costs Malcolm Turnbull’s Government its one-seat majority.

During earlier court hearings, the Government argued Joyce should keep his seat as he was not aware of his New Zealand citizenship at the time. He renounced it in August.

Four other politicians also lost their positions because of their dual citizenship in the same judgment.

Section 44 of the country’s constitution forbids those who are “subject or citizen of a foreign power” are ineligible for election.

Joyce said afterwards: “I respect the verdict of the court…

“We live in a marvellous democracy, with all the checks and balances they have given us all the freedoms we see. I thank the court for their deliberations.”

Turnbull’s Government may recover its majority if Joyce is re-elected to his seat through a by-election.

“The decision of the court today is clearly not the outcome we were hoping for, but the business of government goes on,” Turnbull said.