A record number of informal votes have been lodged in the January 31 state election, the Electoral Commission of Queensland (ECQ) says.

The latest figures show 56,100 Queenslanders voted informally, a figure that is expected to grow as counting continues.

That compared with 53,797 informal votes lodged in 2012 and 46,908 in 2009.

Counting in the 2015 poll is still underway, with the Labor Party on track to win 44 seats and hoping to form a minority government with the support of independent MP Peter Wellington.

By Tuesday night, the ECQ had formally declared the result in 35 of Queensland's 89 electorates.

ECQ spokesman Carrick Brough said they hoped to declare another 30 seats on Wednesday and have all seats declared by Thursday or Friday.

He said the ECQ had received 306,000 postal votes by the 6:00pm Tuesday deadline for their return.

"Postal votes can very much determine the outcome in some seats," Mr Brough said.

Informal vote count 'a concern for major parties'

Dr Tracey Arklay from Griffith University's Centre for Governance and Public Policy said the number of informal votes was disappointing, and that most of them would have been lodged deliberately.

"It's very difficult to cast an informal vote unless you want to do so," she said.

"If you number one box but shade other boxes, your vote is still cast as a formal valid vote.

"That many informal votes suggest there is a lot of disenfranchised people out there who not only don't see either of the major parties working for them, but also don't consider voting for independents or minor parties."

Dr Arklay said it was clearly a message political parties needed to take on board.

"The fact that so many people in this election chose not to influence the decision in any way is a concern," she said.

"If they had all cast a valid vote, perhaps we might have a clearer majority one way or the other.

"Whether they wrote messages or drew funny faces or put an unmarked ballot paper in the ballot box is something that I'm sure there will be a report on, but we won't know who these people are."