As a cloud also hangs over One Nation's Malcolm Roberts, the Senate on Tuesday agreed that the court will look into former minister Matt Canavan and Larissa Waters and Scott Ludlam of the Greens, who have resigned their Senate seats.
It is understood Senator Roberts met with key crossbencher Nick Xenophon in a bid to secure a vote against the motion, but that the Nick Xenophon Team will ignore that plea and vote with the Greens...
It comes amid reports documents, obtained by Buzzfeed, show the senator was once a citizen of the UK.
Senator Roberts today added to the confusion over his citizenship and eligibility for parliament.
"On the facts alone I would support that, but I will listen to the debate", Liberal Democrat senator David Leyonhjelm told AM.
Two Greens senators resigned from parliament last month after discovering they were dual citizens due to their birthplace, while former Turnbull government minister Matt Canavan stepped down from Cabinet this saying his mother registered the 36-year-old Australian-born Queensland senator as an Italian citizen a decade ago, but did not tell him.
Last month, as doubts over his citizenship status increased increased, the One Nation senator says said he wrote to British authorities in June 2016, just days before election nominations closed saying he did not believe he was a British citizen, but "just in case I am, I renounce it, effective immediately".
The High Court will sit in judgement over a government senator and two former Greens members over their eligibility to sit in parliament due to citizenship issues.
'I am looking forward very much to presenting my documents, tendering them in High Court, and let them make the decision.
One Nation Senator Malcolm Roberts has had an awkward slip-of-the-tongue while facing the media over his country of origin.
One Nation leader Pauline Hanson told The Australian newspaper last week there was "no evidence" her party colleague was ever British.