Conservationists say New Zealand is not doing enough to protect Antarctica's Ross Sea.
They want the whole area turned into a marine reserve and the fishing of the lucrative toothfish species to stop.
Officials from the Ministry of Foreign Affairs and Trade are in Hobart this week to discuss which Antarctic waters should be protected and to what extent.
The 25 nations that make up the Convention for the Conservation of Antarctic Marine Living Resources are making their cases, before the body decides next year which areas will become marine reserves.
The Ministry says significant parts of the Ross Sea should be protected, with sustainable harvesting of fish in other areas.
But opponents, including the Last Ocean charitable trust, Greenpeace International and the Antarctic and Southern Ocean Coalition, want protection extended to include the entire area.
They say the Ross Sea is the world's last intact marine ecosystem giving it tremendous scientific value.