Scores of invalid votes for the Queensland Senate may have been registered at Port Douglas over four days as a result of a pre-polling blunder by the Australian Electoral Commission.

Early voters were shocked on Thursday afternoon at Port Douglas Community Hall when it was found that they had been given New South Wales senate ballot papers instead of Queensland senate papers.

The blunder may register hundreds of invalid votes from the seat of Leichhardt, as it was unknown if the incorrect papers had been issued since early voting had started on Monday morning.

Douglas region resident, Malcolm McKellar, says he was shocked to have discovered the mistake when he went to vote at 1pm on Thursday.

“At first I thought I had picked up the wrong How to Vote card from the candidates outside the community centre when I was cross checking it against the Senate ballot paper,” he said.

Mr McKellar said he went to a friend’s house nearby to check the list of Queensland Senate candidates on the internet and came back to the voting place to inform the AEC volunteers of the mistake.

“That was a period of 50 minutes,” he said. “There were six other people in the hall who all handed in their papers when they heard of the mistake – who knows how long this was going on for and how many invalid votes had been registered.”

Mr McKellar said while he had brought it to the attention of the Australian Electoral Commission via Leichhardt MP Warren Entsch’s office, he questioned what would happen with the invalid votes.

“It’s a pretty serious error that may have disenfranchised a lot of people who have already voted,” he said.  “There are a lot of people walking around thinking they have done their duty and voted, and in essence, they haven’t voted at all.”

Mr Enstch told The Newsport the issue was human error and thought it unlikely voters would get to re-cast their Senate vote.

“We still don’t know how many votes are going to be affected in this, there’s no way we can get people back to do this again as there is no way of finding out who casted a vote,” he said.

“Given there is such a period of rather interesting parties and individuals that are contesting and the fact they have done a coalition of independence and exchanged preferences, it’s a serious concern there is a volume of senate votes that will not be counted.

“The fact that it took a member of the voting public to bring this to pick up there was a problem…this is going to affect two states but of particular concern it’s going to be Senate votes in Queensland that are going to be voided.

“It’s upsetting for the people who have come down and voted, and believe in the integrity of the voting system."

UPDATE 10.20am The Australian Electoral Commission has confirmed that voters will not be able to re-cast their Senate vote, but estimates only around 40 voters were affected.

A spokesperson  said the blunder “was isolated to a short period of time” and occurred at the Port Douglas Pre-polling centre only.

“The voters House or Representatives ballot counts, but when counting occurs, the NSW Senate ballots in question are  isolated and are informal,” the spokesperson said.

“The AEC regrets the error and is investigating further.”