When asked if the new Labor leadership team had given away too much to the miners, Mr Rudd replied: ''History will be the judge of that.''

Mr Rudd noted that it was after he was dumped as prime minister that Ms Gillard and Mr Swan elected to make ''some significant changes to the structure of the tax''.

He said it would be up to them to consider any future changes to the tax ''given the fact that it has not collected any real revenue of any significance so far''.

''I'll leave it with them,'' he told Sky News, while emphasising that he did not know what undertakings Ms Gillard and Mr Swan had given the mining industry when they renegotiated the tax in 2010.

The tax was first proposed when Mr Rudd was prime minister - coming out of the Henry tax review - but negotiations with the mining industry broke down.

When Ms Gillard became Prime Minister in mid-2010, she made renegotiating the mining tax one of her top priorities but it has since been argued that the tax was watered down in the process.

It was forecast to raise $2 billion in 2012-13 but last week Mr Swan revealed that it had only raised $126 million in the first two quarters, sparking a renewed push by the Greens, independents and some within Labor to restructure the tax.

Some Labor MPs, such has the Labor Left leader, Doug Cameron, have been backing Labor to have a new ''stoush'' with the mining industry, despite the damage this might do in an election year.

Mr Rudd appeared to agree with that approach.

''No government should ever take a backwards step in pursuit of the national interest,'' Mr Rudd said.

The member for Griffith, who is maintaining a public profile as the government heads towards the polls on September 14, predicted that the year would be ''tough, ugly and bloody''.

He said Labor could win the election but did not specify it would be under Ms Gillard.

''Of course the Australian Labor government can win and can win under the Prime Minister's leadership,'' he said.