The Australian Greens won't block the federal government's mining tax in the Senate if it does not cover gold, but will push for it to be included, the party's leader Bob Brown says.
Labor's proposed minerals resource rent tax (MRRT) covers only iron ore and coal.
However, the Greens have argued for a return to the original 40 per cent resource super profits tax (RSPT), which included all resources.
The party recommended including gold in the MRRT as a first step.
"If Treasury's resource super profits tax were reverted to, which the Greens endorsed, adding gold would bring in $3.5 billion over the next three years," Greens leader Bob Brown told ABC radio.
But if push comes to shove the Greens won't block the MRRT in the Senate if gold is not included.
"We are not going to block the government's tax," Senator Bown said.
"But we do know that $100 billion will be lost over the next 10 years on average through not taking Treasury's advice as the Greens want to."
Senator Brown says most gold producers are foreign owned and more of the profits should remain in Australia.
He says he will argue his case at next week's national tax forum in Canberra.
"Australia is facing a squeeze in government spending," he said.
"We don't know what the future is bringing, but it doesn't look all that bright.
"Why shouldn't we be properly taxing the current resources boom, where the money is largely otherwise going to flow overseas, to ensure that Australians get the proper supply of money for their services, the way the public expects."
The controversial RSPT was dumped last year after Prime Minister Julia Gillard rolled then Labor leader Kevin Rudd and negotiated instead a 30 per cent MRRT with three mining giants - BHP Billiton, Rio Tinto and Xstrata.
The federal government's tax forum will be held in Canberra on October 4 and 5.
