The Green Party is warning that John Key's Government will offer already protected land in exchange for the protected land it wants to mine.

"The Government has withheld 12,189 hectares of existing parks from going into Schedule 4 for almost a year," said Metiria Turei, Green Party Co-leader.

"This can only be for one reason, so they can offer up this conservation land in exchange for the 7,000 hectares of wilderness that they want to mine, pretending this will be a net environmental benefit.

"Meanwhile, the National Party is under pressure from its own focus groups and the public at large who don't want a bar of this cynical sleight of hand."

Last July, Cabinet rejected DoC's assertion that 12,189 hectares of gazetted parks and reserves should already be in Schedule 4, as revealed by a Green Party Official Information Act request.

"It is a cynical waste of taxpayer's money to spend millions fossicking about on protected land while cutting critical budgets like health and education."

"It is time that John Key's Government swallowed the dead rat that is Schedule 4 mining, and re-affirms the cross-party consensus that created Schedule 4 in the first place," Mrs Turei said.