Australian Treasurer Wayne Swan on Thursday promised a re-elected Labor government will not put a tax on carbon during its next term of office.

Opposition treasury spokesman Joe Hockey pressed Swan on the issue on Thursday, demanding to know whether Australia would be hit with a carbon tax in the next three years under Labor.

"We have made our position very clear, we have ruled it out," the treasurer told ABC Television.

Swan said the federal government would look to its citizens assembly for further guidance on the issue of climate change.

The assembly would see 150 randomly chosen Australians consider the need for a carbon price over the course of a year, before the government makes a decision.

"We are to go back to the community and work out a way in which we can put a cap on carbon pollution," Swan told reporters in Canberra on Thursday.

"We are going to do it in a consultative way and we'll do it in the face of the opposition of the Liberal Party and the Greens."

The election date was set on Aug 21.