“I think most Australians would agree that you couldn’t get anyone more Australian than Barnaby Joyce,” Mr Tehan said.

“It has never been raised before that anybody thought Barnaby Joyce wasn’t Australian.

“I think Barnaby Joyce has been absolutely genuine.”

Mr Joyce told Parliament on Monday that he could also be a New Zealand citizen as his father was born there.

New Zealand Prime Minister Bill English later said he had been informed that Mr Joyce was a New Zealand citizen under his country’s laws but the Australian legal system would have to examine the issue.

The Australian Constitution forbids members and senators from standing for election or holding office while holding a dual citizenship, alliance or potential benefit from a foreign nation.

Should Mr Joyce be removed from parliament by the High Court, the Coalition would, at least temporarily, become a minority government.

Queensland LNP Senator Matt Canavan resigned as a cabinet minister last month and took his case to the High Court after it was reveled he was a dual Italian citizen.

Mr Tehan told ABC Melbourne that there was no contradiction in Mr Joyce’s case.

“Matt did what he did, and everyone respected him for it, but time has moved on and we have got more advice and we know more about Section 44 [of the Constitution, which bars dual citizens from office].

“The Prime Minister was able to get advice from the solicitor general, and that advice was clear and therefor what we have done is refer the matter to the High Court.

“We are now waiting for the High Court to make its decision and in the meantime we are getting on with governing the country.”

Prime Minister Malcolm Turnbull told parliament yesterday, in response to opposition attempts to have Mr Joyce’s vote invalidated, the the High Court would find in his favour.

“The leader of the Nationals party, the deputy prime minister, is qualified to sit in this house and the High Court will so hold," Mr Turnbull said.

Mr Tehan denied that Mr Turnbull had tried to dictate terms to the independent High Court.

“The Prime Minister was just putting the case very firmly and very strongly that based on the advice that he has, that he thinks that he has made the right decision.”

Mr Tehan declined to comment on whether it was appropriate for Mr Joyce and Mr Turnbull to criticise and make jokes at the expense of two Greens senators who resigned when they discovered they were dual citizens.