The mining industry spent more than $20 million fighting the Government's resources rent tax before last year's federal election according to figures released by the Australian Electoral Commission.

The Government wanted to impose a 40 per cent tax on the super profits of mining companies.

The industry responded with a massive media campaign.

The new figures show the Minerals Council of Australia (MCA) spent more than $17 million to publicise the industry's opposition to the tax.

BHP Billiton spent more than $4 million and Rio Tinto more than $500,000.

MCA spokesman Ben Mitchell says the investment was worth it.

"We felt the resources super profits tax was poor public policy that represented a clear threat to the viability of Australia's minerals industry, and the size of our campaign reflected the nature of that threat," he said.

A modified version of the tax was passed, with a 30 per cent tax applying to the coal and iron ore sectors.