Conservation Minister Nick Smith says there is no evidence to suggest Maui's dolphins need further protection over and above the measures currently in place.
The International Whaling Commission said the Government must take immediate steps to protect the critically endangered mammals but Dr Smith told Morning Report he will not be taking that advice.
Dr Smith said he does not accept that not enough is being done.
"Set-netting is the biggest risk, we've banned it where the Maui's dolphin exists and I simply challenge the International Whaling Commission and others .. show us the Maui."
The International Whaling Commission has published a report saying the current sanctuaries are not sufficient to ensure its survival.
There are about 55 Maui's dolphins over the age of one left and the commission's scientific committee says if even one more dies it will risk the extinction of the species.
Otago University professor of marine science Steve Dawson said the situation was dire.
"It just does not get more urgent than (the) Maui's dolphin faces. This is the most urgent conservation crisis facing any marine mammal, anywhere in the world."
The report recommends extending a protected sanctuary from Maunganui Bluff to Whanganui, banning gillnet and trawling fishing in protected areas and extending protection to 37 kilometres offshore.
But Seafood New Zealand chief executive Tim Panckhurst said the fisheries were already hurting under the current protections.
"The problem with that is, if you take it to its natural conclusion, you basically close the entire inshore fishery. There has to be room for both conservation and commercial fishing."
The Green and Labour parties support the International Whaling Commission's recommendations.
Labour's conservation spokesperson Ruth Dyson said saving the dolphin would actually benefit fisheries.
"What we could get is a win-win out of this situation. We could support the fishing industry to move to sustainable fishing practices. We could revisit any of the issues of concern to them and get a total win for the Maui's dolphin and for the fishing industry."
Otago University's Steve Dawson agrees with the report's conclusion that there is enough science to prove Maui's dolphins are under threat, and action is needed now.
"What commonly happens is that government servants use the excuse of not having perfect knowledge to delay doing something," he said.
"The International Whaling Commission has taken a really strong stand on this by saying 'look, we absolutely know enough to manage this problem properly, and if we wait until we know everything they'll be gone'."
Mr Panckhurst said no one wanted to see the extinction of the Maui's dolphin, and believes the conservationists and the fishing industry can move forward together.
The International Whaling Commission issued a similar call for urgent government action in a report two years ago.