Sydney: Australia’s conservative government will have to wait at least two months to discover if key members will survive a dual citizenship crisis that has put its one-seat parliamentary majority under threat.

Seven lawmakers from across the benches have so far run afoul of an obscure constitutional rule which bars dual citizens from parliament.

The Liberal-National coalition’s slim majority in the lower house is on the line after Deputy Prime Minister Barnaby Joyce discovered he had New Zealand citizenship.

A court ruling disqualifying him could potentially topple Prime Minister Malcolm Turnbull’s government.

Five cases — Joyce, National Party senator Matt Canavan and three other senators from minor parties — were referred to the High Court, with the chief justice determining Thursday that they would be heard on October 10-12.

“There is an obvious public urgency in relation to this matter to clarify the situation,” Attorney-General George Brandis told reporters.

“We look forward to the speedy resolution of the matter.”

Brandis said the court would examine seven cases during the three-day seating in Canberra.

The total includes another two senators caught out by the law, the Nationals’ Fiona Nash and independent Nick Xenophon.

The government had hoped the hearing would occur in September to dispel uncertainty created by its biggest crisis since it was returned to power in mid-2016.

The saga began in July, when Greens co-deputy leader Scott Ludlam resigned after revealing he had dual Australian-New Zealand citizenship.

Other politicians followed, including Canadian-born Greens senator Larissa Waters and Canavan, who stepped down as resources minister after finding his mother signed him up to Italian citizenship in his 20s.

Australia-born Joyce — the leader of the rural-based Nationals — earlier this month found out he had automatically acquired New Zealand citizenship through his Dunedin-born father.

Nash, Xenophon and Indian-born One Nation senator Malcolm Roberts have also been under a British citizenship cloud.

Xenophon told Sky News on Wednesday he wanted a citizenship audit of all lawmakers, adding: “If I’m in strife, then there will be dozens of others in strife in the parliament.”

Despite the cloud hanging over his government, Turnbull has repeatedly expressed confidence that the High Court would not disqualify the politicians.

“I am very, very confident that the court will find that those members that have been caught up in this dual citizenship issue by reason of descent will be found not to be disqualified,” he told reporters Wednesday.

The dual citizenship rule was originally inserted into the 1901 constitution to ensure parliamentarians were loyal solely to Australia.

However, critics say it is out of step with the country’s modern reality, where 50 per cent of the population are either foreign born or the children of immigrants.