Senator Matt Canavan could leave politics if High Court rules he's ineligible to sit in parliament

Coalition Senator Matt Canavan might walk away from politics altogether if the High Court rules he’s ineligible to be in parliament.

Speaking ahead of three days of hearings before the court's Full Bench in Canberra, the stood-aside minister said he and his legal team were still confident the court will rule in his favour.

“This is something that does need to be resolved in terms of Constitutional clarity,” Senator Canavan said.

But the Queenslander told 9NEWS if the court rules against him, he might give up a political career, after talking to his wife.

Senator Canavan is one of seven politicians whose fate will be determined by the High Court, including deputy prime minister and Nationals leader Barnaby Joyce.

Deputy Nationals leader and cabinet minister Fiona Nash, former Greens Senators Scott Ludlam and Larissa Waters, NXT leader Nick Xenophon, and One Nation’s Malcolm Roberts will all have their cases heard.

Most interest will focus on Mr Joyce, who has New Zealand citizenship as a result of his father being born there.

He didn’t realise until recently that could make him a dual citizen, which under section 44 of Australia's constitution renders a person ineligible to sit in parliament.

He’s since renounced it.

However, if the court rules against him, the government will lose its one-seat majority in the House of Representatives, forcing Mr Joyce to re-contest his New South Wales seat of New England at a by-election, likely before the end of the year.

It’s unclear how soon the High Court might hand down the decisions, though parliament resumes next week with the government anxious for an outcome.  

However, the Prime Minister Malcolm Turnbull appears not to be contemplating a court loss.

“The government - based on the legal advice we have from the solicitor-general - is confident that (Mr Joyce) and the other two senators, Nash and Canavan, will be found not to be disqualified from sitting in the parliament,” Mr Turnbull said.