Canberra, Oct 10 (IANS): An Australian court on Tuesday began a long-awaited hearing into whether seven MPs caught up in a dual citizenship row should remain eligible for office, the media reported.

Under constitutional rules, Australian politicians cannot be dual citizens, reports the BBC.

The High Court of Australia will clarify whether there are any exceptions, such as for those who did not know they were dual nationals.

If Deputy Prime Minister Barnaby Joyce is disqualified, the government could lose its one-seat majority.

The cases involve Joyce and his government colleagues Fiona Nash and Matt Canavan, as well as four politicians from minor parties - Malcolm Roberts, Nick Xenophon, Larissa Waters and Scott Ludlam.

The government will argue that only two politicians who "voluntarily obtained, or retained" dual status should be disqualified.

The hearing will last three days. A ruling could be made as early as Thursday, the BBC reported.

The citizenship revelations began in July when New Zealand-born Ludlam, from the Greens, announced he was a dual national.

It prompted dozens of politicians to make public statements about their status.

The court will hear submissions from the seven politicians, the government, and an independent challenger.