Moscow and Beijing plan to wrap up a decade of talks on supplies of Russian natural gas before President Vladimir Putin's expected to travel to China next month, a deputy prime minister said on Monday.

Deputy prime minister Arkady Dvorkovich, speaking after a visit to China last week, also said Chinese companies wanted to invest in the former Ukrainian peninsula of Crimea taken over by Russia last month.

"On gas, the talks are drawing to a close, and there's a common intention to finish this work before the Russian president's visit in May of this year," Dvorkovich told a government meeting chaired by Prime Minister Dmitry Medvedev.

Gazprom and CNPC signed a framework agreement in 2009 which could eventually see almost 70 billion cubic metres of Russian gas sent to China annually for the next 30 years.

The talks over the past decade have become mired in differences over pricing and the final contract has proved elusive.

Russia has in recent years sought to align itself more closely with China as it seeks to unlock new energy markets in Asia and those efforts are expected to intensify in the face of a fresh confrontation between Moscow and the West over Ukraine.

The signing of the gas contract would be a scoop for Putin after the United States and the European Union slapped sanctions against some of his closest allies following Russia's takeover of Ukraine's peninsula of Ukraine.

Analysts have said that China is likely to use Russia's growing isolation from Western markets to negotiate a lower price.

Dvorkovich said that during talks last week he had won a pledge from the Chinese to invest in the impoverished Crimean peninsula whose takeover by Russia was condemned by the West as annexation.

"We've agreed that we will take a look at new projects including in our new regions and our Chinese colleagues who are involved in alternative energy are eyeing with interest taking part in these projects in the Republic of Crimea," said Dvorkovich.

He also said Russia and China agreed to boost cooperation in coal, power, oil and oil products.