I might pay no tax, says mine magnate

With critics saying proceeds from the tax will fall well short of revenue targets, Mr Forrest yesterday stepped up his attack on the government, blasting forecasts that it will raise $10.6 billion as a "charade".

He also escalated his war of words with the Treasurer, Wayne Swan, who has accused Mr Forrest of using his wealth and influence to pursue vested interests.

"I would say we will pay between zero and $50 million of MRRT [minerals resource rent tax] some time in the next five years I am not sure when it is and it will depend on iron ore prices. But will it raise the $10 billion? No," Mr Forrest said at the National Press Club in Canberra.

If accurate, the prediction suggests Fortescue would receive hefty concessions under the tax. Stockbrokers expect the company's pre-tax profits to exceed $20 billion in the next five years.

Mr Forrest's prediction is the latest blow to the government's forecasts after the chief executive of BHP Billiton, Marius Kloppers, last month said it was "impossible" to say how much mining tax it would pay. Treasury expects that BHP, Rio Tinto and Xstrata which helped design the tax will pay 90 per cent of the tax between them.

However, Mr Forrest said the multinational miners had "fleeced" the government in the secret talks, which took place after Labor dumped Kevin Rudd as prime minister in mid-2010.

Mr Forrest has threatened to challenge the mining tax in the High Court.

Mr Forrest, whose speech was about improving employment among indigenous Australians, also blamed the federal government for the weak condition of the economy, saying its decisions had made businesses more uncertain.

Asked if he would consider entering federal politics, after billionaire miner Clive Palmer this week sought preselection to run in Mr Swan's electorate, Mr Forrest said: "I would be surprised if Mr Swan contests that seat because I think a three-legged dog would beat him to it."

A spokesman for Mr Swan said Mr Forrest, and the opposition, did not "want Australians to share in the benefits of the resources that we all own".

"They can stand up for vested interests and their mining profits the government will keep standing up for working Australians by using the mining boom to increase superannuation, tax breaks for small businesses and invest huge amounts in infrastructure," the spokesman said.