The Australian Electoral Commission says it had no power to remove Liberal party signs alleged to have misled Mandarin-voters at a polling booth in Melbourne.
This was despite a staff member confirming the translation of the sign as an instruction to vote "the correct way".
Controversy over the signs - which were a similar colour to the official Australian Electoral Commission signage - has led to a legal challenge over the election of Treasurer Josh Frydenberg and Liberal MP for Chisholm Gladys Liu. The case will be heard by the full bench of the Federal Court in less than three weeks.
Under questioning from Labor senator Don Farrell during Senate estimates on Tuesday night, Australian Electoral Commissioner Tom Rogers said he did not want to comment extensively on the case while it was before the courts.
The electoral commission's chief legal officer, Paul Pirani, said he became aware of the signs when alerted to a tweet by Victorian Trades Hall Council secretary Luke Hilakari.
Mr Hilakari said the posters read "the correct way to vote is to put a number 1 next to the Liberals and number every other box", and appeared to be written like an official AEC instruction to voters.
Mr Pirani said it wasn't immediately obvious the signs were authorised by the Victorian Liberal Party, so the commission did its own investigation.
Once the authorisation was confirmed, the electoral commission found the signs did not breach electoral laws, Mr Pirani said.
"Did the AEC engage a translator on the day to determine what the signs actually said?" Senator Farrell asked.
"The answer to that is no. We saw in one of the tweets that we received had a translation of what the message was on those signs and we accepted that at prima facie value. We did check it later on in the day because one of our staff members speaks Chinese and she confirmed the translation that was contained in the tweet was reasonably accurate," Mr Pirani said.
But even if the signs were deemed to be a problem, Mr Pirani said the commission was powerless to remove them unless they were within six metres of the polling place.
"So even if the sign is, you deem the sign to be misleading voters ... you still wouldn't remove that sign?" Senator Farrell asked.
"We have no power to remove the sign, the normal process is we would first ask the campaign workers to voluntarily remove the sign. If they refused to do it my only option is to go to court under section 383 of the commonwealth electoral act to seek an injunction order that the signs to be removed but we have no power ourselves to go out and order the removal of signs," Mr Pirani said.
Mr Rogers said the "vast majority" of parties and candidates voluntarily took down signs if the commission found an issue with them.
"99.99 per cent of the time they absolutely do that and expeditiously as well," Mr Rogers said.
Electoral officials also revealed the cost of holding the May election was $342 million.
Asked how increased use of prepolling had impacted the commission's resources, Mr Rogers said no one would sit in that chair and say they did not want more funding.
However he said questions around the future of pre-polling were a matter for the parliament.
If the pre-poll period was shortened though, Mr Rogers believed there would be greater usage over a shorter time.
"It's a service citizens are using and they appear to value the service," Mr Rogers said.