More than 9500 hectares of ocean off the West Coast has become a marine protected area (MPA).
The West Coast Marine Protection Forum, made up of representatives of tangata whenua, commercial and recreational fishers and environmental groups, had pushed for the area.
Minister for Primary Industries Nathan Guy and Minister for the Environment Maggie Barry announced the new protected area - made up of three stretches of ocean - this afternoon
Mr Guy said the new area would be a major boost to protecting and improving marine biodiversity.
Commercial fishing methods that damage the sea bed would be banned in the new MPA although some fishing would still be allowed.
All fishing is already banned in the marine reserves near the new area.