The proposal, put forward by the United States and New Zealand, would create a 600,000 square mile reserve in the Ross Sea, a deep antarctic bay south of the Pacific Ocean.
In a release Tuesday the Pew Charitable Trusts foundation, which has backed the reserve effort, said it would equal about 70 percent of the amount of global ocean currently fully.
At a meeting of the Commission for the Conservation of Antarctic Marine Living Resources, Russia's delegation said further clarification was needed to determine whether the commission was legally entitled to establish marine protected areas in the Ross Sea, RIA Novosti reported.
A World Wildlife Fund representative said it was believed Russia opposed the plan because it would affect the nation's fishing industry.
"I wouldn't call the situation hopeless," the WWF's Polina Zhbanova said, noting Russia "made some compromise proposals that balanced the country's interests and environmental needs, but other countries have to show willingness to compromise too."
The commission would consider compromise proposals at its upcoming annual meeting in Australia, Zhbanavo said.