The Federal Opposition says if the mining tax gets through Parliament it will not scrap the associated boost to superannuation.

Under Labor's proposal the mining tax would fund a 1 per cent company tax cut.

The tax cut is designed to help employers cover the cost of a gradual increase in the employer superannuation contribution, from 9 to 12 per cent.

Opposition frontbencher Eric Abetz has confirmed the Coalition is backing away from a pledge to rescind the increase.

"Our view is to oppose the totality of the mining tax," he told Sky News.

"[But] in the event that it does get through the Parliament and the super gets legislated, then our view is that should be retained."

Senator Abetz defended the party's new stance on the issue, saying decisions had to be made on a case-by-case basis.

Finance Minister Penny Wong wants to know how the Opposition will pay for the superannuation changes if it is scrapping the mining tax.

"We saw this backflip on super, which they say now they will deliver without the revenue source of the mining tax," she told Insiders.

"This is just another number of hundreds of millions of dollars that they're going to have to add to the $70 billion worth of savings they're going to have to find before the next election.

"At some point they're going to have to be accountable for that."

Deputy Greens leader Christine Milne also wants to know how the Opposition will fund the increase in super contributions.

"Every day we see [Opposition Leader] Tony Abbott out there with the big blast of the trumpet, the blood oath, he's going to repeal everything," she told Network Ten.

"Then there's the cowardly retreat."

Last week the Government introduced legislation for its minerals resource rent tax to Parliament.

The measure will require coal and iron ore miners to pay a 30 per cent tax on their super profits from July next year.