By Gleb Bryanski

MOSCOW, March 19 (Reuters) - China and other emerging nations back Russia's call for a discussion on how to replace the dollar as the world's primary reserve currency, a senior Russian government source said on Thursday. Russia has proposed the creation of a new reserve currency, to be issued by international financial institutions, among other measures in the text of its proposals to the April G20 summit published last Monday.

Calls for a rethink of the dollar's status as world's sole benchmark currency come amid concerns about its long-term value as the U.S. Federal Reserve moved to pump more than a trillion dollars of new cash into the ailing economy late Wednesday.

Russia met representatives of China, India and Brazil ahead of the G20 finance ministers meeting last week, as the big emerging powers seek to up their influence on decisionmaking globally. Their first ever joint communique did not mention a new currency but the source said the issue was discussed.

"They (China) did not formally put forward their position for the G20 summit but unofficially they had distributed their paper regarding the same ideas (the need for the new currency)," the source told Reuters, speaking on condition of anonymity.

The source said the Chinese paper envisaged the International Monetary Fund's Special Drawing Rights (SDRs) being first assigned a role of a clearing currency on some transactions and then gradually becoming the main global reserve currency. "They said that the role of reserve currency should be given to SDR," the source said.

A U.N. panel of experts is also looking at using expanded SDRs, originally created by the International Monetary Fund in 1969, but now used mainly as an accounting unit within similar organisations as a new reserve currency instead of the dollar.

Currency specialist Avinash Persaud, a member of the U.N. panel, told a Reuters Funds Summit on Wednesday that the proposal was to create something like the old Ecu, or European currency unit, that was a hard-traded, weighted basket.

The SDR and the old Ecu are essentially combinations of currencies, weighted to a constituent's economic clout, which can be valued against other currencies and against those inside the basket.