The caution comes as a Sydney eBay user has attempted to hawk his vote for at least $1500.

The listing, titled “buy my vote”, asks bidders: “What is the plebiscite worth to you?”

“The reason I’m selling my vote is because either way I don’t care but thought there are people who do,” the user writes in the product description.

The seller assures part of the auction proceeds will go to “help kids battling cancer”, but the charitable act has hit a snag.

The agency in charge of the vote, the ABS, has warned that a response that has been bought or sold “would likely an offence against the Census and Statistics Act 1905 or the Commonwealth Criminal Code”.

The ABS said the offence against the Census and Statistics Acts could carry a maximum penalty of $2100, while a potential criminal offence could see offenders jailed for up to 12 months.

The agency also said it had contacted several sites about the possibility of people selling their ballots, and eBay and Facebook had confirmed any votes for sale would be blocked and removed from their sites.

With some details of the ballot yet to be released, it is not yet known if voters will have to prove their identity or sign a declaration as they lodge their vote.

The Australian Bureau of Statistics will start mailing out forms for the postal ballot on Tuesday, after the High Court dismissed a challenge to the eight-week national survey.

With fears the debate could turn ugly, Labor will work with Finance Minister Mathias Cormann over the weekend to draft laws ensuring all campaign material is authorised and there is balance in its broadcasting.

Senator Cormann said legislation could clear parliament next week if there was consensus.

“We want the process to be fair to both sides of the argument,” he told Sky News.

South Australian Senator Nick Xenophon said the attempted eBay sale was a sign urgent legislation and clarification around the process was needed.

News.com.au has contacted the vote-seller but they declined to speak without payment.