Environmental groups say the government's extension of set net bans off the Taranaki coast won't save the Maui's dolphin.
The government is extending set net bans along the Taranaki coast, out to two nautical miles, and the use of set nets between two and seven nautical miles will be prohibited unless there is an observer on board fishing boats.
Primary Industries Minister David Carter says they are an interim measure while risks facing the remaining Maui's dolphins, estimated to number 55, are reviewed.
But WWF New Zealand says the measures won't save the dolphins.
"There are now fewer Maui's dolphins than kakapo left in the world," said Rebecca Bird, WWF New Zealand's marine programme manager.
"And yet this decision means the government is knowingly allowing a method of fishing that kills dolphins to go ahead in their habitat.
"Instead of seizing the opportunity to give Maui's the best chance for survival and population recovery, these measures are simply not enough to protect the species from extinction."
Ms Bird said the measures didn't protect them from gillnet fishing and trawling, and the marine corridor between the South and North Islands and harbours were also largely unprotected despite being an important habitat for the dolphins.
Forest and Bird advocacy manager Kevin Hackwell says the measures are an improvement but not good enough.
"The set net ban needs to be extended to all regions where these nationally-critical Maui's dolphins are found. That includes all harbours and offshore to the 100m depth contour."
Labour and the Green Party objected on similar grounds, with Labour conservation spokeswoman Ruth Dyson saying New Zealand's clean and green reputation would be in shreds if the dolphin becomes extinct.
"They have refused to follow international best practice ... they have bowed to the fishing industry, ignored independent advice and taken an approach that has a high risk of failure."