Unsuccessful Labor candidate Sarah De Santis says she should have won the ultra-marginal Victorian seat of Ripon because she received an "absolute majority" of votes.
Ms De Santis' lawyer Olaf Ciolek appeared for a directions hearing in the Court of Disputed Returns on Thursday, claiming the result would have been different if the "right steps" had been taken during vote counting.
The electorate was handed to incumbent Liberal member Louise Staley by just 15 votes on a two party-preferred basis after the November 24 Victorian election.
The outcome came on December 8 after a recount of first preferences and informal ballots.
Ms De Santis first indicated she would mount a court challenge in December and has since lodged her petition and affidavit.
"My client's case will be that evidence will show ... the Electoral Commission didn't declare my client to be elected despite receiving an absolute majority of votes," Mr Ciolek said.
He said the recount of preferences was done in error.
Lawyers for Ms Staley and the commission were also present in court on Thursday.
Ms Staley's lawyer Daryl Williams QC argued Ms De Santis needed to show which ballot papers hadn't been dealt with correctly, and that she needed to show the results might have been different.
The court could order a recount after a hearing into the matter, which is likely to be held in April.
Justice Melinda Richards said she would need to decide if there would be anything gained from a recount.
Australian Associated Press