At 0930 GMT the rouble was 0.9 percent weaker against the dollar at 65.80 and 0.6 percent weaker against the euro at 77.45.

The price of international oil benchmark Brent was down around 0.9 percent on Wednesday to $46.15 per barrel, hovering slightly above a six-year low.

The rouble had been down 1.6 percent against the dollar on opening, but trimmed its losses after Finance Minister Anton Siluanov said the ministry planned to convert part of its Reserve Fund into roubles.

The central bank will gradually convert some 500 billion roubles ($7.6 billion) from the country's Reserve Fund that has been pencilled in to support the budget this year, he said.

Siluanov said the ministry could invest part of the Reserve Fund in rouble bank accounts to take advantage of the weak rouble and earn high interest.

He also said that if oil averages $50 per barrel this year the budget would lose around 3 trillion roubles in revenues, calling for expenditure cuts except in defence.

Russian stock indexes were mixed on Wednesday, with the rouble-based MICEX index up 0.5 percent at 1,540 points, and the dollar-based RTS index <.IRTS> down 0.1 percent at 737.

(Reporting by Jason Bush, Editing by Elizabeth Piper)