Former Labor senator Anne McEwen has failed to introduce new evidence which could have helped her challenge retired Family First senator Bob Day's eligibility to run for election.
Ms McEwen is party to the High Court challenge to Mr Day's re-election in 2016 which relates to his alleged personal financial interest in his Adelaide office, which would breach the constitution.
The office - which was leased by the government - was sold to a friend of Mr Day in 2014, but Mr Day's company allegedly loaned money to make the purchase and was ultimately liable for the mortgage.
If proven it could lead to Mr Day's senate vacancy being filled by another party such as One Nation or Labor, making the numbers in the Senate trickier for the Turnbull government.
Ms McEwen lost her SA Labor senate seat at the election but could return to parliament if the challenge succeeds.
Her legal team on Tuesday asked the High Court for permission to obtain evidence from political expert Simon Jackman.
Simona Gory, for Ms McEwen, said a report by Mr Jackman suggested the 2016 vote was "distorted" because Mr Day's popularity boosted his minor party's vote.
It raised questions of whether Family First would have received the same number of votes if Mr Day's name had not been on the ballot paper, the court heard.
Legal counsel for Mr Day and the attorney-general opposed Ms McEwen's application, saying they had no time to respond to the "partisan and partial" report, which shouldn't be relied upon.
Justice Michelle Gordon was scathing of Ms McEwen's late request and rejected it.
She said it failed to give the other parties enough time to test the analysis.
"Experts do not make findings, courts do," she added.
The parties will return to court on Monday and Tuesday before the matter is heard before the full bench next month.
It's unusual for the High Court sitting as the Court of Disputed Returns to hear evidence from witnesses.
