The Green Party is calling for an extension of the fishing ban to protect one of the rarest species of dolphin, Maui's dolphin.
Researchers estimate there are only 55 adult Maui's dolphins left in the world.
Currently a set-net ban exists on the northwest coast of the North Island from Taranaki to Northland.
Green Party oceans spokesperson Gareth Hughes says current restrictions are not enough to save the dwindling species and he wants the ban to cover all of the North Island's west coast.
Commercial fisheries are being blamed for the dolphin's demise but the New Zealand Seafood Industry Council says natural causes may also be responsible and more research is needed.