A powerful coalition of conservation groups backed by entrepreneur Sir Richard Branson is calling for an Antarctic fishing ban within an area half the size of Australia.
The Antarctic Ocean Alliance proposes a 3.6 million sq km marine reserve in the Ross Sea to protect the biodiversity hotspot, which is home to huge proportions of the world's emperor penguins, orcas, and the Antarctic toothfish, keenly sought after by wealthy American diners.
The region, 3000km south of New Zealand, is described as "The Last Ocean" because of its relatively untouched state and "the lungs of the planet" because of its huge absorption of CO2.
The Alliance's New Zealand spokesman, Geoff Keey, said that on the surface Antarctica was frozen and sparsely populated. But its underwater world teemed with crucial marine life which thrived on the abundance of microscopic plants and animals.
He said its ecosystem was rare because it still had good numbers of top-end predators such as seals, orcas, and the slow-moving toothfish.
New Zealand - one of 24 nations with a stake in Antarctica - has proposed a marine-reserve scenario to protect some parts of the Ross Sea from fishing. It will present the plan to the region's ruling body, the Commission for the Conservation of Antarctic Marine Living Resources, in November.
But critics say the area covered by the plan does not include spots that are rich in toothfish, which is the cornerstone of the Antarctic food web.
At present, international accords prevent more than 3800 tonnes of toothfish being caught between December and August. Mr Keey expects the fish-rich Ross Sea to come under increasing pressure - from legal and illegal fisheries - as fish stocks deplete around the world.
Three New Zealand companies operate in the region but most of the catch does not end up on New Zealand plates because it is a delicacy that fetches around $70/kg in the United States.
The Antarctic commission has agreed to develop a network of marine reserves. But the alliance believes the process could be slow-moving or ineffectual without public pressure.
The Green Party, which backed the proposal, has said that getting the Government onside could be difficult because the local fishing industry has huge political clout.
The alliance presented the marine reserve proposal to politicians and guests in Wellington last night.
Environment Minister Nick Smith said a number of proposed marine reserves were on the table - including around the Kermadec Islands - and Government needed to make well-informed, balanced decisions.
"If we are going to create additional reserves, which sometimes can be justified, we want to be sure we fully understand what economic opportunities we may be pushing to one side.
"In areas like the Kermadecs and the sub-Antarctics and the Ross Sea, we actually have pretty poor information about resources that are there. We would want to better understand that before we made those choices."
The alliance is made up of international environment groups such as Greenpeace and WWF, and is supported by Sir Richard, founder of Virgin Group and an environmentalist, and UN Biodiversity Ambassador and actor Edward Norton.