Signs telling Chinese Australians to vote Liberal in the federal election were designed to look like they came from the independent electoral commission, a key party figure says.
The Chinese-language corflutes were posted across polling booths, including in the electorates of Kooyong and Chisholm, on election day in May.
When translated, the purple and white signs - in the colours used by the Australian Electoral Commission - say the "correct" way to vote is to put the Liberals first.
Failed Kooyong candidate Oliver Yates is challenging Treasurer Josh Frydenberg's re-election in court, and climate campaigner Vanessa Garbett is challenging the election of Chisholm MP Gladys Liu, alleging the signs broke the law.
Their lawyer Lisa De Ferrari SC quizzed former Victorian Liberal Party director Simon Frost in the Federal Court in Melbourne on Wednesday.
"You intended to convey the impression that this was an AEC corflute, didn't you?" Ms De Ferrari said.
Mr Frost, now an advisor to Mr Frydenberg, took a long pause before replying: "It was similar to the AEC colours, yes."
"So the answer to my question is yes?" Ms De Ferrari pressed.
"Yes," Mr Frost replied.
It came after he said the messages on the signs, displayed across seven Melbourne electorates in both simplified and traditional Chinese script, were different to what had been approved by the party.
"The translation was not as I had given ... as it was re-translated back through the media," Mr Frost said.
The court was told he had intended the message to be: "to make your vote count, put a 1 next to the Liberal candidate."
Mr Frost said he chose not to use the Liberal logo on the purple corflutes and conceded he didn't think at the time about whether they were likely to mislead or deceive voters.
Both Chisholm and Kooyong have a significant number of residents of Chinese heritage, and the corflutes were displayed at 42 polling places across Chisholm and the 37 in Kooyong.
Both Mr Frydenberg and Ms Liu knew about the corflutes and allowed them to be displayed, Ms De Ferrari says.
She added they were a "public wrong of some great importance" and is seeking the "drastic measure" of voiding the MPs' elections.
"The principle, we say, is also important and too important to have those considerations of practical inconvenience take over," Ms De Ferrari said.
The AEC has denied the posters were likely to mislead or deceive voters into thinking they were official instructions from the commission.
It urged the court to throw out the cases.
Outside court, Mr Yates said the case showed the electoral commission had "failed dismally".
"The idea that we have political parties engaged in misleading and deceptive conduct at election time is appalling," he told reporters.
"There should be no need for a case like this. We shouldn't have to be running this case, the AEC should be running this case."
The case is due back in court on Thursday.
Australian Associated Press