New Zealand has again been heavily criticised by international experts for its lack of progress on protecting Māui dolphins.

The latest report from the scientific committee of the International Whaling Commission (IWA) said it continued to have grave concerns for the dolphins' future.

There are about 60 of the species left and the commission has called for immediate action to be taken to stop them being caught up in gillnets in their habitat.

Its report said current protections fell well short of the IWC recommendation to ban gillnet and trawl fishing from Maunganui Bluff to Whanganui, offshore to 20 nautical miles and including harbours.

Currently, less than 20 percent of the dolphins' habitat was protected.

A member of the IWC scientific committee, Dr Liz Slooten from Otago University, said the dolphins were teetering on the edge of extinction.

"We've gone well past the point where it's possible to accurately count even the living dolphins, let alone how many are being killed in fishing nets.

"We simply need to remove the threat rather than continuing to study the threat," she said.

The commission was very clear that doing more research was not a substitute for protecting Māui dolphins, Dr Slooten said.

The Ministry for Primary Industries, which regulates the commercial fishing industry, has not yet responded to RNZ's request for comment.