THE sister of One Nation founder Pauline Hanson could be set to replace embattled Senator Malcolm Roberts if it's deemed he was ineligible to be elected.

Judy Smith has emerged as the unlikely frontrunner to enter federal Parliament's upper house as a One Nation representative, as the political dual citizenship scandal widens.

Questions continue to mount about Roberts' apparent British citizenship and whether it was renounced prior to his election last year.

The Daily Telegraph reported today that he was a member of parliament­ for six months before getting confirmation he had relinquished any additional citizenship he may have had.

Mr Roberts­ was born in India to an Australian mother and Welsh father. Documents show he travelled on a UK passport at age one. He became an Australian citizen in May 1974 and has since only travelled on an Australian passport.

Senator Malcolm Roberts.
Senator Malcolm Roberts. Kym Smith

Should he go, his replacement would likely be Queensland businessman Fraser Anning, however Fairfax Media reports he is embroiled in bankruptcy proceedings, potentially ruling him ineligible.

The next person down would therefore be Smith, who ran in the unwinnable fourth place position on One Nation's senate ticket in 2016.

She has in the past described herself as one of Hanson's biggest supporters.

RELATED: One Nation Senator Malcolm Roberts engulfed in dual citizenship saga

The party's website states: "Judy share (sic) the same values as Pauline and would like to help strengthen her cause in the Senate, by her side."

Greens senators Scott Ludlam and Larissa Waters were forced to resign when it emerged they were citizens of New Zealand and Canada respectively, in addition to Australia.

Government minister Matt Canavan will head to the High Court after it was revealed his mother signed him up with Italian citizenship.

And now Roberts, a controversial One Nation figure, faces a similar fate. Fairfax reports the Turnbull Government is considering referring the matter to the courts.

Judy Smith visiting her sister Pauline Hanson in prison in 2003.
Judy Smith visiting her sister Pauline Hanson in prison in 2003. News Limited

Under Section 44 of the Constitution, a citizen of two or more countries is ineligible for Parliament.

Canavan stood aside from Cabinet after it was revealed his mother had signed him up for Italian citizenship more than a decade ago, making him a dual citizen and ineligible for federal Parliament.

The validity of the citizenship will be tested in the High Court as Senator Canavan has said it was done without his consent or knowledge.

Originally published as Pauline's sister could be set for Senate