Bottom-trawling fisheries have been banned from a 10,000 hectare area off the West Coast of the South Island.
Government confirmed three new "marine protected areas" for the West Coast today.
The three MPAs will prevent "mobile, bottom-impacting" fishing methods in the region, while allowing some other fisheries to operate.
Conservation Minister Maggie Barry said the new protections were a "win-win situation" because they protected marine life without significantly impacting on fisheries.
The MPAs were designed to complement five existing marine reserves on the West Coast, where fishing was banned altogether.
The region is known as a habitat for treasured species including the Hector's dolphin and blue penguin.
Primary Industries Minister Nathan Guy said the protected areas were the result of years of hard work by the West Coast Marine Protection Forum, which was made up of local government officials, local Maori, fishing and environmental groups.
"I applaud their willingness to seek constructive compromises, which has helped to balance protection and use of the marine environment," Mr Guy said.
New Zealand has 44 marine reserves in total, and a series of marine protected areas. The no-take reserves cover around 10 per cent of New Zealand's territorial waters - the 12km boundary around the coastline.