The Abbott government will cut funding to Australia's $3 billion renewable energy agency by $435 million, details of its carbon tax repeal legislation reveals.

The Coalition had flagged a cut to the Australian Renewable Energy Agency (ARENA) when it released its pre-election costings, but at the time refused to detail how big it would be.

Before the election, a spokesman for Treasurer Joe Hockey said of the ARENA cut: "As a result of the state of the budget due to Labor's continuing mismanagement, it is necessary to make reductions."