The Federal Opposition has seized on reports the mining tax raised no revenue in its first three months of operation, declaring Treasurer Wayne Swan ought to be sacked.

Monday's budget update predicted the tax would raise $2 billion during the current financial year, but The Australian newspaper has reported that no money was collected in the first quarter.

Defending the figures this morning, Mr Swan twice blundered over how much money the tax would raise this year.

He told reporters in Brisbane the tax would raise $9 billion this financial year, confusing the figure with revenue projections for the next four years. On the third attempt, he got the figure right.

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"We are forecasting over $9 billion in revenue over the forward estimates for the MRRT, and that represents the Treasury's best judgement of where those revenues are," Mr Swan said.

"The design of a resource rent tax is such that it delivers the revenue when profits are high, and in the case of commodities, when prices are high.

"And of course when they go down, well it doesn't necessarily deliver the same amount of money.

"In the past few months, we've had a real crash in commodity prices."

Since the budget was released in May, the Government has been forced to slash the forecast for this year's mining tax revenue by $1 billion.

Shadow treasurer Joe Hockey says it is now clear why the Government released its budget update on Monday, before the mining tax revenue figures were available.

"The mining tax will be the signature illustration of the failure of the Gillard Government," Mr Hockey told ABC radio.

"Julia Gillard personally negotiated the design of the new tax with Wayne Swan and the mining industry, and now we have a revelation that it's not raising a cent.

"Only Labor could introduce a new tax that doesn't raise a single cent, but has billions of dollars of expenditure against it.

"What's worse is, the Government knew this was coming and brought forward Monday's budget announcement to avoid revealing the true state of the mining tax."

Opposition assistant treasury spokesman Mathias Cormann says Mr Swan should be sacked for shackling mining companies with extra compliance costs for no extra Government revenue.

Opposition Leader Tony Abbott says the tax has damaged investor confidence and raised perceptions of sovereign risk, even though it has not raised any money.

The bulk of the tax was expected to be paid by BHP Billiton, Rio Tinto and Xstrata - the three companies involved in negotiating the design of the tax with the Prime Minister and the Treasurer.

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Labor frontbencher Simon Crean says the tax was designed so companies only pay it when profit levels reach a certain point.

"It was never projected to raise (revenue) in the early part... because these mining companies are making massive investments in infrastructure - which is tax deductible," Mr Crean told Channel Nine.

"So arguing that this is a failure based on the first three months is just ludicrous."

The revelations about the mining tax revenue come amid the fallout from the collapse of talks designed to cut the company tax rate.

The Business Tax Working Group, set up by the Government last year, had been looking at options for changing other business charges to fund a cut.

Late yesterday, it released a draft final report saying it could not come up with a revenue-neutral package that all participants could agree to recommend.

The Australian Chamber of Commerce and Industry (ACCI) says the process was "doomed" from the outset, and it is not surprised the working group has failed.

"They were basically asking a business group to identify what tax arrangements they want to give up to actually afford a company tax reduction," ACCI spokesman Greg Evans told ABC Radio National.

"Those tax arrangements were very important to particular industries, such as in the area of depreciation arrangements, research and development provisions, the deductibility of certain expenses for mining."

Mr Swan says he is disappointed the group could not reach an agreement on how a company tax could be paid.

"The Government shares the aspiration with the business community that over time we should bring down company taxation," he said.

"But we're not going to do that by hitting the battlers in the street.

"The terms of reference for the business tax working group were for them to look at savings in the business tax system to fund an overall cut to the company tax rate, and I'm disappointed that they couldn't agree on how that should be done.

"But nevertheless, we will continue to work with the business community."

Labor has pointed the finger at the Coalition for opposing a previous attempt to cut the company tax rate that was linked to the mining tax package.

But Senator Cormann says the collapse of the business tax working group shows that easing the tax burden on business is clearly not a priority for the Government.

"First we had the mining tax fiasco which is ongoing, then we had the broken promise on the carbon tax and now we've had the collapse effectively of Labor's hand-picked panel," he said.

"Labor's tax reform process in now in complete chaos."