The Government will allow mining exploration in marine mammal sanctuaries that protect rare dolphins, whales and seals.

Conservation Minister Kate Wilkinson defended a decision for seismic surveying and mining exploration to go ahead in marine sanctuaries, saying surveying could be restricted to minimise harm to marine mammals.

Yesterday Prime Minister John Key ruled out mining in World Heritage Sites.

Green MP Gareth Hughes said it made a sham of so-called marine mammal sanctuaries after oil companies were granted 10 permits in four of the protected areas.


"It's great that you won't be going ahead with mining in World Heritage sites but what about the marine mammal sanctuaries," he said.

There were six existing sanctuaries around New Zealand's coastline meant to provide a permanent refuge for marine mammals in fishing waters.

Ms Wilkinson said another eight new sanctuaries were being set up.

Mr Hughes said marine mammals like the hector's dolphin, the endangered Maui's dolphin, whales and fur seals would be threatened by the exploration.

He said there was "legitimate concern" about seismic surveys - where airguns are used to produce powerful underwater sounds.

The Government says it will regulate seismic testing by placing observers on surveying ships and reviewing a 2006 code of practice.

Scientists have said air guns could cause deafness in animals if they're too close.

Otago University marine scientist, associate professor Steve Dawson said he had been asked for his advice on how the surveying would affect wildlife and it had been ignored.


He said marine mammals had been found to strand themselves as a result of acoustic surveying and could go deaf from the sound.

"The only things that are louder than air guns in the ocean are significant explosions and lightning strikes."

"This makes a mockery of the so-called marine mammal sanctuaries that the Department of Conservation has because they don't protect the animals from the major risk to them which is fishing and they establish a few extra steps that anybody wanting to do a seismic survey has to go through, but it's really only a slight impediment," he said.

"I am disappointed the Government would do something that is disingenuous by calling something a sanctuary when it isn't."