Some fiscal trickiness has lead to a zero dollar tax bill for mining giants Rio Tinto, with reports other resources groups could get off scot-free as well.

As it stands, the MRRT forces companies to estimate their exposure and make pre-payments every three months, but the actually bill is not worked out until after the conclusion of the financial year. A refund from Rio’s pre-payments in April has meant the company effectively pays nothing.

The revelation has reportedly raised the prospect that other mining companies could be looking to dodge the tax-man as well in what could be a damaging blow to recent government budgetary estimates.

There have been volleys fired at the Federal Government this week over the lack of actual revenue from the resources rent tax, compared with estimates from over a year ago.

A pre-election financial statement released last week came with the prediction the tax would raise $4 billion over the next four years, well below the original prediction of $22.5 billion.