A bid to get marine protection for the Ross Sea has failed for the fifth time - but China and Russia have indicated they could support it in the future.
Twenty-four countries and the European Union have been discussing the proposal at the two-week annual Commission for the Conservation of Antarctic Marine Living Resources in Hobart.
The 34th round of discussions was chaired by Russia who has, with China, previously blocked attempts to get protection for the Ross Sea.
This year's meeting was described as crunch time for the proposals, which have not got over the line.
For a reserve to be created, all 25 members of the Commission for the Conservation of Antarctic Marine Living Resources have to agree to it.
Last year, 22 countries and the European Union supported the proposal but Russia and China blocked it.
However, China said it would support a revised proposal for the protection of the Ross Sea and Russia said it would be open to working with members on the move ahead of next year's meeting.
But environment advocates say the proposal has already been watered down during the past five years.
Foreign Minister Murray McCully described China's support for a revised marine protection areas (MPAs) as a "major step forward in reaching the consensus required to put workable protections in place for the Ross Sea".
The revised proposal, which was still being developed, included a new Antarctic krill research zone which was designed to promote research and scientific understanding of krill in the north-western Ross Sea region.
"Directed fishing for krill will also be permitted in the existing Special Research Zone of the MPA, in addition to the limited fishing for toothfish that is already provided for in that zone," Mr McCully said.
The total size of the MPA had increased to more than 1.5 million square kilometres, of which more than 1 million square kilometres was a no take zone.
Mr McCully said he also welcomed Russia's statement that it is open to working with members on the protected area ahead of the next year's meeting.
"We continue to strive for the establishment of an MPA in the Ross Sea. It remains challenging, but support for the proposal continues to build," Mr McCully said.