A proposal to create the world's biggest Marine Protected Area (MPA) in Antarctica is on the agenda once again at an international meeting in Hobart.

For the fifth consecutive year the Commission for Conservation of Antarctic Marine Living Resources (CCAMLR) will discuss whether to support proposals for marine protected areas in the Antarctic.

One proposal is for the East Antarctic and was put forward by Australia, France and the European Union in 2010.

Australian scientists say the area supports important ecosystems and contains distinctive deep water flora and fauna.

The East Antarctic MPA has been endorsed three times by CCAMLR's scientific committee, but in order to be approved it requires unanimous support from all 25 member nations.

Last year it was blocked by China and Russia.

The World Wide Fund for Nature's Bob Zuur is hopeful China will be on side this year.

What is CCAMLR? Commission for the Conservation of Antarctic Marine Living Resources set up in 1982

Commission for the Conservation of Antarctic Marine Living Resources set up in 1982 International body with 25 member nations, 11 others support convention behind CCAMLR

International body with 25 member nations, 11 others support convention behind CCAMLR Monitors fisheries and ecosystems to determine policies to conserve marine life

Monitors fisheries and ecosystems to determine policies to conserve marine life Sets catch limits on all fisheries in Antarctic waters

Sets catch limits on all fisheries in Antarctic waters Based in Hobart

"There was a very positive meeting between president Obama and president Xi Jinping a month ago, and China said that it would work with the United States towards the protection of the Ross Sea, he said.

But he is less convinced about Russia's support.

The other proposal for an MPA is in the Ross Sea and was put forward by the United States and New Zealand.

It proposes to protect around 1.25 million square kilometres, and would be the world's biggest MPA.

Mr Zuur said he was worried about what would happen to the areas if they are not protected.

"Fishing can occur in areas has threats to penguins, to whales, to sea lions and the rest, and that the area becomes more vulnerable to the changing climate, those would be the key risks if those areas aren't protected," he said.

Mr Zuur said both proposals had been revised and have a good chance of gaining unanimous support.

"This is the fifth year, so this is really crunch time each year that it's come through both proposals have become smaller, and we've now actually got duration specified so they're no longer permanent," he said.