Two of the nation's top constitutional experts believe he may have been invalidly elected and believe the High Court should consider the matter. Senator Malcolm Roberts. Credit:Alex Ellinghausen If Senator Roberts is ruled invalidly elected the seat would normally go to the next person on the One Nation ticket, who is in this case Queensland businessman Fraser Anning. However Mr Anning is the subject of a bankruptcy application lodged in the Federal Court on July 19. The constitution prevents people who are found to be bankrupt from serving in Parliament. Fairfax Media alleges no wrongdoing by Mr Anning and the application to make him a bankrupt may not proceed. The application relates to Great Southern Limited, a managed investment scheme which collapsed in 2009. Thousands of investors faced financial ruin after the collapse of the scheme, which had invested in agricultural business including timber plantations and cattle properties.

Mr Anning is being pursued by the Bendigo and Adelaide Bank. The matter will be first heard in court on August 22. Judy Smith, who is the sister of One Nation leader Pauline Hanson. Credit:Robert Rough If the bankruptcy application is successful, the seat would likely fall to Judy Smith, one of Senator Hanson's six siblings, who ran on the unwinnable fourth position on the ticket. Ms Smith describes herself as "extremely proud of her sister" and says she has "always been by Pauline's side, giving her full support". Questions have been raised over the status of One Nation senator Malcolm Roberts.

"Judy shares the same values as Pauline and would like to help strengthen her cause in the Senate, by her side," the One Nation website notes. A senior Labor source said the opposition expected the government to refer Senator Roberts to the High Court when Parliament resumes. If it does not, it may consider moving its own motion. Sean Black – now working for One Nation Senator Malcolm Roberts. Credit:Facebook. Greens leader Richard Di Natale said Senator Roberts should be treated the same as every other MP. ​"Senator Ludlam and Senator Waters have acted with integrity and we will be referring their cases to the court of disputed returns. One Nation should do the right thing and refer Malcolm Roberts as well. If they fail to do that we will support a referral," he told Fairfax Media.

Crossbench senator Nick Xenophon said: "If eminent constitutional experts are saying there is a case to answer then i think the government should act." Anne Twomey from the University of Sydney said Senator Roberts must clear up two pressing questions - when his renunciation took effect and exactly what steps he took before nominating to renounce. If he did not do enough than there was a "strong case" for a referral to the High Court, she said. University of New South Wales expert George Williams agrees the key question is exactly what Senator Roberts did prior to nomination. If he did not do enough "he is likely to be disqualified". "There is enough here to cast real doubt over his eligibility to remain in the Senate. His case, along with the others, should be referred to the High Court," Professor Williams said. Fairfax Media put clarifying questions to Senator Roberts' office but they refused to answer. Senator Roberts' senior media adviser, Sean Black, threatened to report journalists to police.

"Your persistent emails, despite requests to stop, is classified by our office as stalking," Mr Black said in an email. "Any continued pestering or harassment from you or your colleagues of anyone, including me, from our office or organisation will be referred to the Queensland police. Loading "This issue is now over. Stop the harassment. Please find another victim." Follow us on Facebook