Work to protect endangered Hector's dolphins will be accelerated, the government announced today, after five were found dead in a fisherman's net in the last month.

The small pod was killed in a set-net as the vessel fished off Banks Peninsula.

There are only about 10,000 Hector's dolphins left in the world and they are endemic to New Zealand.

Entanglement in nets is the number one cause of death to these rare creatures and fishing has caused major population declines.

The International Whaling Commission and scientists from all around the world have demanded better protection for the marine mammals.

Set-netting is not and it's understood the vessel was not doing anything wrong or fishing in a prohibited area.

1 NEWS understands the vessel's skipper is "devastated" and the fishing company involved have changed their fishing practices.

In a release today, Fisheries Minister Stuart Nash and Conservation Minister Eugenie Sage said options for the protection of Hector's dolphins include a new threat management plan, reviewing the use of set nets, considering extending the set net ban on Banks Peninsula Marine Mammal Sanctuary, encouraging voluntary closures of some fisheries, and stepping up observers or camera coverage on fishing boats.

"The deaths of these dolphins is distressing," Mr Nash said.

"The fisherman did the right thing by coming forward to report the catch, as legally required ... there were no observers or cameras on his boat.

"The Chief Executive of FINZ advises me the fisherman deeply regrets the capture and has now decided to stop set netting in the area.

"I am also advised he appears to have been fishing outside the area closed to set netting, although MPI compliance staff are still assessing the incident."

Ms Sage called the deaths "needless" and said set nets in the habitats of endangered species is an "ongoing problem".

"Having a serious look at how to best phase out these near invisible and deadly mono-filament gill nets is long overdue," she said.