The world's biggest marine reserve in Antarctica may have to be given an expiry date to get countries with interests in the prized waters to agree to it.
Delegations from 25 nations will resume talks in Hobart today on a New Zealand-US proposal for a marine protected area (MPA) in the fish-rich Ross Sea, 3500km south of New Zealand.
The proposed reserve has been scaled back from 2.27 million sq km to 1.34 million sq km after a consensus could not be found at a special meeting of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) in Germany in July.
At that meeting, nations including Japan and Norway expressed concern about the permanence of a marine reserve in the Ross Sea.
New Zealand's proposal now included a 50-year "sunset clause", which meant the reserve could be revised or scrapped if countries felt it was not working.
New Zealand officials said there was a wide range of views on a cut-off date - some countries felt 50 years was too long, while others wanted the MPA to last forever.
Antarctic Ocean Alliance co-ordinator Geoff Keey said that like National Parks, marine reserves should be permanent: "There's always the risk that some countries will try to make it more of a temporary closure."
But he added if the revised proposal got over the line, it would be difficult to dismantle it because any changes required a 25-nation consensus.
The talks in July failed after Russia and Ukraine questioned whether CCAMLR had the authority to establish a marine reserve. The two countries were believed to have dropped that line of argument, but both nations remained concerned the proposal could affect their fishing interests in the region.
The failure to get a consensus was a hugely disappointing outcome for the New Zealand and US delegations because the meeting had been called especially to discuss the MPA proposals and had been preceded by eight months of furious lobbying.
The discussions over the proposed reserve have dragged on for two years and the policy has been worked on for eight years.
Conservationists were initially dismayed at the downsizing of the reserve but New Zealand officials have emphasised that its core parts remained intact and it would be still be the largest marine reserve in the world.
A decision on the reserve was expected on November 1.