International efforts to create two vast marine sanctuaries to protect the pristine wilderness of Antarctica failed Friday for the fifth time, but delegates said China's support for one reserve and Russia's commitment to further talks gave them hope.

The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) meeting closed Friday with no agreement on the two proposed areas, designed to protect species including whales and penguins.

Officials said China had at the last minute indicated it would support one of these reserves in the Ross Sea, which is known as the "Last Ocean" because it is considered the only intact marine ecosystem left on Earth.

But it was ultimately blocked by Russia, which along with China also stopped a proposal for a marine protected zone in the East Antarctic coastal region, the Antarctic Ocean Alliance of environmental groups said.

"It is appalling that while the majority of CCAMLR members are more than ready to create significant marine protected areas in Antarctic waters, China and Russia have blocked efforts to negotiate a successful outcome," said the alliance's Jill Hepp.

Both proposals have now been shot down five times at the annual CCAMLR meetings, which require consensus from all 24 members countries and the European Union to progress.

But delegates welcomed China's support for the Ross Sea sanctuary, which it had blocked in previous years, saying it made a future deal more likely.

"That's important because now only one country remains that isn't supportive and so we're closer. This is an important country to have gotten on board," head of the US delegation Evan Bloom told AFP.

New Zealand's Foreign Minister Murray McCully also welcomed China's support as a "major step", saying the proposal was designed to balance scientific, environmental and fishing interests.

"We also welcome Russia's statement that it is open to working with members on the MPA ahead of the next CCAMLR meeting in 2016," he said.

The head of the Russian delegation could not be reached and the foreign ministry in Moscow declined to comment, as did the Chinese foreign ministry.

- Stunning accomplishment -

The US and New Zealand-backed Ross Sea proposal was this year enlarged to more than 1.5 million square kilometres (600,000 square miles) although the overall no fishing zone was slightly reduced to about 1.1 million square kilometres.

The second proposed protected area, the Australia, France and EU-backed East Antarctica sanctuary, is for a one million square kilometre zone over four areas where some fishing and research would be allowed, with environmental restrictions.

Both reserve proposals have been on the table with CCAMLR -- a treaty tasked with overseeing conservation and sustainable exploitation of the Antarctic Ocean, also known as the Southern Ocean -- since 2011.

Each has been modified as members have debated how to manage the region, which environmentalists say is home to more than 10,000 unique species, including seals and colossal squid. It is also critical for scientific research.

Andrea Kavanagh, director of the Pew Charitable Trusts, said she took hope from China's change of direction and the fact that Russia had said it was willing to work with other members on the proposals.

"This is a stunning accomplishment to come out of this particular meeting when there was so much disagreement and dissention on the floor," she told AFP.

Ultimately, however, she said the talks were a replay of the previous four meetings, bringing no relief for the millions of animals that live in Antarctic waters.

"What is most disturbing about this year's failure is the systematic disintegration of CCAMLR's ability to deliver on its mandate for marine protection," said Mark Epstein, executive director of the Antarctic and Southern Ocean Coalition.

The failure of the Antarctic deals came after New Zealand, Chile and the Pacific state of Palau have recently announced new marine protection zones.