The citizenship scandal which has rocked Australian politics claimed a third victim on Tuesday, with resources minister Matt Canavan resigning from Cabinet after claiming his mother signed him up as an Italian citizen in 2006 without his consent.

Canavan's announcement followed Greens senators Larissa Waters and Scott Ludlam's resignations from politics in recent weeks after the pair fell foul of Section 44 of the Constitution, which makes dual citizens ineligible to run for parliament.

There has also been speculation around the possible dual citizenship status of Roberts, the One Nation senator who was born in India to a Welsh father and reportedly became a British national.

In the last 24 hours, BuzzFeed News sent extracts from online databases to the senator, which appear to show Roberts not only listed as a British national, but that he once travelled with his family on a UK passport.