If the cabinet votes in favor of ratification, the bill would pass to the State Duma lower house of parliament, a chamber where the nation's main pro-Kremlin party holds a two-thirds majority.

The pact, signed in 1997 in the ancient Japanese city of Kyoto, cannot enter into force without Russia's agreement after the United States rejected it in one of the first decisions made in office by President George W. Bush.

An unidentified government official predicted to the official RIA Novosti news agency that the cabinet would approve the pact and forward it to the State Duma.

"There will be a positive decision," the news agency quoted the official as saying. "The Kyoto pact will be approved and there will be instructions on clarifying the conditions of its implementation."

Last week Russian President Vladimir Putin's administration, which has for years hesitated over whether to give final approval, ordered five ministries to consider the ratification.

Ecologists hailed the move, which clears a hurdle towards submitting the protocol for ratification by the Russian parliament, but warned that powerful opponents within the government would still try to sabotage the decision.