In Canberra, pre-polling opens three weeks before election day, with 26 per cent of voters taking advantage of this to vote early at the most recent ACT election.

Electoral Commissioner Phillip Green has suggested that, given the large number of pre-poll votes, the territory could get rid of a single “election day” and simply have a voting period. This would also allow more electronic voting, he said.

But Mr Corbell, appearing on Friday before an inquiry into the running of elections and the coming change from 17 to 25 seats, said there was an argument that people might change their vote before election day depending on events during the campaign.

“The argument being made is given the large number of people that vote before polling day ... whether or not that is having an effect on the ability of the campaign period as a whole to properly inform the elector as to all of the issues at play in the election,” he said. But he stressed the government had not taken an official view.

Also at the inquiry, Labor and the Greens are pushing for a lower cap on the amount candidates can spend in election campaigns, with the bigger Assembly set to blow out the spending limits. At present, candidates can spend up to $60,000 in their bid to get elected, which allows a party to spend just over $1 million for the 17 candidates. When the Assembly moves to 25 seats at the next election, the $60,000-a-candidate rule would allow them to spend $1.5 million.

Greens convenor Sophie Trevitt has called for a spending cap of $45,000 a candidate, with a maximum of $500,000 a party. Labor branch secretary Elias Hallaj also supported $45,000, saying recent elections had been an “arms race” of soaring spending. In 2001, both major parties spent well under $500,000, according to ACT Electoral Commission figures. The amount has risen steadily since, with Labor always outspending the Liberals. In 2012, Labor spent $920,000 and the Liberals $740,000.

Mr Hallaj also called for more scrutiny of advertising, saying hundreds of thousands of dollars had been spent on television and radio advertising, as well as newspapers and website advertising in 2012. Mr Green has pointed out that candidates are already required to report considerable detail on their advertising spend, with nearly $1 million spent overall by the parties on broadcast advertising, and $108,000 on newspaper advertising, at $24,000 on theatre advertising. The figures show the Liberals concentrated on broadcast ads, spending $480,000 and just $5500 on newspaper ads, while Labor spent $277,000 on broadcast and $87,000 on newspaper ads.

Ms Trevitt and Mr Hallaj both made submissions to the Assembly inquiry, which is also looking at whether rules that stop unions and other groups from donating to campaigns are unconstitutional, after similar laws in NSW were ruled unconstitutional and verturned.

The law says that organisations including unions can’t donate to political campaigns – to donate, you must be an individual and on the electoral roll. This was overturned in NSW and looks set to be here as well.

The ACT law also says that, if “associated entities” spend money on a campaign, the spending counts towards the total a party is allowed to spend. In NSW, the section refers to “affiliated organisations” (such as unions) and was ruled unconstitutional, but it is not clear whether a court would make the same ruling on the ACT rules. The idea is that while "affiliated organisations" such as unions operate quite separately from political parties and their spending shouldn’t be lumped in with party spending, "associated entities" can be a lot closer. Labor has the Labor clubs and the 1973 Foundation, both established by the party and both sending profits back to Labor, and the Liberals formerly had the 250 Club.

Mr Green argues associated entities should be considered part of the party for the election spending rules. “If associated entities are not included within a party … it is arguable that this could be a vehicle for circumventing the cap on expenditure to an unacceptable extent,” he said, while acknowledging the point could be challenged in court.

But Mr Corbell argues that the point is less clear cut and suggested the combined spending cap might only need to apply to very close connections, such as when an associated entity was controlled by a party or Assembly member.