A Federal Court judge has questioned how Josh Frydenberg's election victory could be overturned due to allegedly misleading posters, given the Liberals' resounding win in the seat.
A failed candidate and a climate campaigner are trying to void the May re-election of the federal treasurer in the Melbourne seat of Kooyong and fellow Liberal MP Gladys Liu's victory in nearby Chisholm.
The challengers claim Chinese-language Liberal ads, which when translated say the "correct" way to vote is to put the Liberals first, are illegal because they misled or deceived voters.
But one of three Federal Court judges tasked with deciding the case says even if Chinese-speakers in Kooyong changed their votes, Mr Frydenberg would still have have won by a margin of 4329.
"What you want us to do is say notwithstanding that case, taken at its highest, accepting everything, we should declare Mr Frydenberg not elected," Justice Andrew Peter Greenwood told the challengers' lawyer Lisa De Ferrari SC on Friday.
"How can we possibly do that?"
It came after the MPs' lawyers said neither challenger could show even a single Chinese-speaking voter complained about being misled by the purple and white signs.
The Liberals had earlier admitted the signs were deliberately created in the same colours used by the Australian Electoral Commission.
Despite the "dramatic" admission by former Victorian Liberal Party director Simon Frost, there was no suggestion he had misled or sought to mislead voters in casting their ballots, Philip Solomon QC said.
But for the colours, the corflutes and AEC banners looked nothing like each other, the lawyer argued.
He conceded the former could have been "more obviously partisan" but said Labor had used purple signs in a previous Bennelong by-election.
Mr Solomon added it was "laughable" that Chinese-speaking voters had arrived at polling booths "steeled to vote one way" but then "determined that they were being commanded when casting their ballot to vote for the Liberal Party".
Regardless of this, there simply were not enough voters in either seat who only spoke Chinese to have affected the outcomes, the lawyer said.
Mr Frydenberg came out of the May 18 poll with a 5.7 per cent margin and Ms Liu beat Labor by about 1000 votes.
The three judges hearing the case have reserved their decision.
Meanwhile, the federal Greens have referred the Victorian Liberals to the federal police over the corflutes.
It came after a "clear admission that they were trying to impersonate a Commonwealth body," Greens Senator McKim said on Friday.
Australian Associated Press