Conservation groups say a new government proposal to help the world's rarest marine dolphin, Maui's dolphin, is inadequate and will not save the species from extinction.

Conservation Minister Dr Nick Smith has proposed a 350 square kilometre extension to the set net fishing ban off the coast of Taranaki to increase protection for Maui's dolphins, of which scientists estimate only 55 are left.

The move will extend the zone south as far as New Plymouth from Pariokariwa Point and out seven nautical miles, but this is "entirely inadequate" and will do little to save the dolphins from extinction, said Forest & Bird.

Instead, Forest & Bird is campaigning for a comprehensive Maui's dolphin sanctuary - in which gill nets, trawling, mining, and seismic testing would be banned - throughout the dolphins' habitat.


"Scientists say that in order for the Maui's dolphin to survive, we can afford for only one dolphin to be killed every 10 to 23 years, so obviously urgent action is needed," said Forest & Bird marine advocate Katrina Subedar.

Maui's dolphins appear on the International Union for the Conservation of Nature's 'red list' of threatened species, and are considered to be the animal most at risk of extinction in New Zealand.

International conservation organisation WWF said it supports increased protection but the current proposal does not go far enough.

"Instead of a proposal, we believe the government should act to protect Maui's immediately," said WWF-New Zealand executive director Chris Howe.

"The reality is that despite the minister's words today, Maui's are still at risk from being caught in fishing nets. For a species on the brink of extinction, that's not acceptable."

Maui's dolphins live only along the west coast of the North Island and net fishing, the biggest threat to their survival, is only banned in some parts of their range.

Public opinion research earlier this year found the majority of New Zealanders want Maui's dolphins protected throughout their range.

The Colmar Brunton polling revealed 77 per cent of people support an expansion of the ban, 14 per cent did not know, and 9 per cent were opposed to expanding the ban.

"The majority of New Zealanders care about the future of our dolphins and we encourage people to speak out and make their views known during the consultation period," said Mr Howe.

To save the species, a sanctuary which prohibits harmful fishing practices and marine mining activities - from Maunganui Bluff to the Whanganui river mouth, including harbours and out to 100 metres deep - is needed, he said.

Over 70,000 submissions were received by government for the Threat Management Plan Review by November last year, the majority of which were in favour of increased protection for Maui's.