The Government is considering changes to the Environmental Protection Authority, after the guardian of the seas turned down two offshore mining applications.

The EPA is responsible for protecting the ocean around New Zealand, and the Government is debating changes to the agency which will decide who gets to prospect for oil and mine offshore.

"New Zealanders don't want these kind of mining proposals to go ahead so the Government should actually respect that instead of working on behalf of the mining industry," Greenpeace Aotearoa New Zealand executive director Russel Norman said.

The EPA recently rejected plans to mine iron ore off the Taranaki coast and a phosphate mining venture in the Chatham Rise.

Currently the EPA chooses the members of its "decision making committees" - experts who spend months deciding whether to allow activities in an area stretching 200 miles out to seas. But the changes would see the Government make the appointments.

Conservationists believe the EPA's independence is now under threat.

"Once you politicise the approval process with a government that is fully committed to pretty unrestricted mining then clearly you are going to get an outcome of more mining and more environmental destruction," Mr Norman said.

Environmental Minister Nick Smith would not confirm the proposals he's taking to cabinet.