A joint New Zealand-US proposal to create the world's largest marine protected area in Antarctic waters has finally got across the line.

Foreign Affairs Minister Murray McCully confirmed this afternoon that member countries of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) had agreed to the sanctuary in the Ross Sea after talks in Hobart this week.

The marine protected area (MPA) will cover roughly 1.55m square kilometres, of which 1.12m sq km will be a no-take zone.

"New Zealand has played a leading role in reaching this agreement which makes a significant contribution to global marine protection," McCully said.

Now that it has the approval of the 25 countries which govern the Antarctic, the MPA will come into force in December 2017.

It is one of New Zealand's major foreign policy objectives, and it has taken six years of diplomatic wrangling to get all countries to agree to the proposal.

CCAMLR decisions require a consensus, and proposals can fail if any single country objects. Previous attempts to reach agreement have been scuppered by opposition from fishing countries, mainly Russia and Ukraine.

McCully lobbied his Russian counterpart Sergei Lavrov on the issue during a recent trip to Moscow.
United States Secretary of State John Kerry - who has a strong interest in marine protected area - had also held talks with Lavrov.
"At a time when relations on so many fronts are difficult with the Russians, some co-operation and a constructive dialogue is very pleasing to us."