Greens leader Christine Milne is urging the government to rework the mining tax as a senate inquiry into the tax begins.
Pressure has been mounting on the federal government to ‘fix’ the tax after it was revealed it only raised $126 million in its first six months.
A figure well below the full-year forecast of $2 billion.
The Greens, who say loopholes were created during the negotiation process, have been calling for the tax to be patched up to provide funds for the Gonski education reforms, the national disability insurance scheme and Denticare.
The Greens had called for mining loopholes to be closed earlier this year, which allowed mining companies to deduct the market value of existing assets over many years instead of subtracting the book value over five years.
Proposed changes include increasing the tax rate to 40%, cutting Commonwealth refunds of state royalty increases and including other minerals as part of the tax
"Fix the mining tax – the money is there to be had," Milne told reporters today, The Australian reported.
"Witness after witness makes it perfectly clear the government did a deal with the mining companies which essentially gave the government a political win and the mining companies a massive profit win," she said.
According to SMH, leading economist Ross Garnaut told the senate enquiry that the mining tax is flawed and may not raise any revenue if left as is.
Garnaut blamed state government royalties and the ability of larger miners to lower their mining tax exposure by citing the market value of existing mines as partly responsible for the low tax rate.
‘‘Transitional arrangements for past expenditures on what becomes profitable projects are matters of complexity,” Garnaut told the hearing.
‘‘The way chosen in this case is extreme in its generosity to the established projects,’’ he said.
BHP Billiton, Rio Tinto and Xstrata also appeared before the committee on today.
BHP Billiton and Rio Tinto both say they made payments to the mining tax, but could not yet reveal how much due to market disclosure rules.
It is believed BHP had previously paid $77 in December, while a March quarter payment was Rio’s first contribution to the tax.
It was estimated that BHP and Rio alone would provide between $1 billion and $1.5 billion in MRRT payments in 2012-13.
During negotiations with mining giants BHP Billiton, Rio Tinto and Xstrata, Labor agreed they could deduct state royalties from their mining tax liability.
The agreement means that when a state increases mining royalties on coal or iron ore, the tax’s earnings were reduced.
In February Australian Mining reported that Julia Gillard blamed the state governments for the failed mining tax after many increased royalties paid to the state.
Industry groups argue that any changes to the tax could have a negative affect on the industry.
Minerals Council of Australia chief, Mitchell Hooke, wants taxes on mining companies left as is in order for the industry to remain internationally competitive.
“Full crediting of royalties is a key feature of the MRRT's design, one that ensures double taxation is avoided and that delivers a measure of stability and predictability to the overall tax burden on coal and iron ore projects, which are already at the upper end of global mining tax rates,” Hooke said.
“Even before the introduction of the MRRT, coal and iron ore were among the highest taxed industries in Australia based on the two main fiscal instruments used to collect mineral resource revenues – State and Territory royalties and Commonwealth company income tax.”
“We should be looking at how we can be internationally competitive for investment and jobs for the benefit of Australians today and future generations rather than how we can keep carving up the pie.”
Hooke warned that Australia’s mining industry is in danger of losing its competitive advantage as it was taxed above the global average.
“The industry's effective tax rate is in excess of 42 per cent against a global average of 39 per cent.”
A spokesman for the Treasury has previously said that while the loopholes in the tax were being discussed with the states governments, there were no immediate plans to change the MRRT.