The head of campaigns for the World Wide Fund for Nature in New Zealand says an international report shows the Government is failing to prevent the extinction of the Maui's dolphin.
The report by the International Whaling Commission said the death of even one dolphin would increase its extinction risk, and that the Government's measures to stop them being caught were falling short.
It said the Government should close down any fisheries that were known to pose a risk of bycatch to dolphins.
WWF New Zealand's Peter Hardstaff said the Government needed to get on with it, and talk to fisheries about transitioning to less-threatening methods.
"When they're saying they've got grave concerns, what they're actually saying is this is a conservation emergency...when they say our Government is falling short of implementing the necessary protection, we're failing - our Government is failing to do what's necessary," he said.
"And when they urge the highest priority to be given to eliminating risk to Maui's dolphins, they mean we've got to get on with it, and protect this beautiful creature."
Mr Hardstaff said the population was on the brink, and New Zealand needed to be doing the maximum possible to protect the species, not the minimum it could get away with.
"Our Government needs to come to the table and talk to fishing communities about a transition - we need to get the threat out of Maui's dolphins' habitat, but we need to help fishing communities transition away from the methods that can harm dolphins," he said.
Mr Hardstaff said it was vital to learn to co-exist with the dolphins, and not be a threat to them.
"We need to make sure people can have a livelihood as well, and we believe that's totally possible, and we need the Government to start working with fishing communities to make it happen," he said.
"It doesn't mean we can't fish - there are other fishing methods we can use, there may be other ways we can earn a living, so people can still fish and not be a threat to Maui's dolphins."
He said the Government had only made incremental changes that had not gone far enough.
But Minister of Conservation Maggie Barry said the Government had never disputed the dolphin's critical conservation status, and its protection remained a high priority.
"Extensive protections for Maui's dolphin, based on scientifically verified research, are already in place," said Ms Barry.
"The Government has banned set netting across more than 6000 square kilometres of the coastal marine environment and there is 100 per cent observer cover on set net boats operating within the two to seven nautical mile area outside the restricted zone."
Ms Barry said there had been no verified deaths of Maui's dolphins in set nets or trawl nets since 2002.