Maui's dolphins get extra protection from 26 December, but legal action will still be taken against the Government.
As few as 55 of the dolphins over the age of one are thought to exist.
An extended set-net fishing ban now covers 350 square km off the coast of Taranaki, at a distance of between two and seven nautical miles offshore.
There will also be mandatory observer coverage on boats fishing in that area; monitoring for which the Government is paying $400,000.
But the Nabu group says it will take legal action against the Government because the measures are weak and will not help.
Conservation Minister Nick Smith is not worried about a court case, saying the Government's decision is based on scientific evidence.