Julia Gillard's new minority Labor Government has been accused of trying to "slide away" from a deal to hold a comprehensive tax summit, as questions emerge about the role the mining tax will play in funding $10 billion worth of sweeteners for rural Australia.

Labor clung to power yesterday by just one seat after securing the backing of key independents Tony Windsor and Rob Oakeshott.

Under its deal with Mr Windsor, Labor has agreed to hold a tax summit by 2011 to discuss all the options put forward by the Henry Tax Review.

But Treasurer Wayne Swan has ruled out bowing to Mr Windsor's demands that the resources rent tax be part of the review.

And Mr Swan has also confirmed that $6 billion of the $10 billion regional assistance package which helped to secure the independents' backing will come from the mining tax.

Speaking this morning, Mr Windsor said he had been under the impression the mining tax would be up for discussion.

He has indicated he is not happy about its exclusion and says he wants talks with Mr Swan.

"That's the first time I've heard of that," he told Radio National. "I thought it was going to be included in any discussions in relation to taxation and the Henry Review."

Mr Swan says the Government is already committed to the tax and if independents want to discuss elements of the legislation they can.

"Tony Windsor and the independents will have views about the design of that tax which they can express to the Government, but we have to move forward with legislation," he said.

Mr Swan says he spoke to Mr Windsor about the issue today.

Opposition frontbencher Christopher Pyne has accused the Government of already trying to back out of its deal with Mr Windsor.

"Labor is already sliding away from the deal they made with the country independents but because they are supporting the wrong party there's very little they can do about it," he told Radio National.

"They are stuck supporting Labor when their seats, their history, their instincts, should have been telling them to support the Coalition.

"These two will have all the joy of sitting on a prickly pear for the next few years while they support the Labor Party."

Nationals Leader Warren Truss has slammed the regional assistance package.

"When you look at this $9.9 billion, $6 billion is coming from the mining tax over a period of 10 years, so it's only going to trickle in country areas," he told AM.

"But worse than that the mining tax is going to cost thousands of jobs in regional Australia and so this will have a net loss effect on those people who live outside the capital cities."

Under the leadership of Kevin Rudd the Government angered the mining industry by pledging to introduce a 40 per cent tax on resources in order to fund a superannuation boost and a cut in the company tax rate.

But when Julia Gillard replaced Mr Rudd as Prime Minister she lowered the rate of the tax to 30 per cent and offered other concessions to the industry in a bid to end the stoush.

The Greens, who will hold the balance of power in the Senate next year, support lifting the tax back to its original level.