Speaking to media on a teleconference this morning, Power said FMG’s legal team were being briefed on the MRRT case.

“We would expect to launch that challenge in the coming weeks,” he said.

He added that the challenge was “looking solid”

It comes after the company announced it was seeking legal advice when the MRRT passed through the Senate last month.

FMG director of development Peter Meurs told a conference last month that the company was prepared to pay more tax.

“We’re not against a tax – we just don’t like a tax that’s like this one.”

Meurs said the tax favoured big players and disadvantaged smaller companies starting out.

“We’re in a better position than most but we think it’s discriminatory,” he said.

Western Australian Premier Colin Barnett has previously expressed support for the challenge, while new Queensland Premier Campbell Newman has reportedly expressed interest in being involved.

Barnett has reportedly reiterated support for the challenge today but rather than join it, the state government would be prepared to give evidence in the case.

Meanwhile, miners are facing another blow in next month’s federal budget if the government follows through on its plans to cut the diesel fuel rebate.

FMG chief financial officer Stephen Pearce said he would be “incredibly disappointed” if the rebate was cut.

He said the company already used around 350 million litres of diesel and the removal of the rebate would cost of $140-150 million per annum at those levels.

“That will increase as our fuel usage increases with the expansion,” Pearce told journalists this morning.

This story first appeared on ILN's sister publication MiningNews.net.