Russia's reserves, the world's fourth largest, stand at $526.4 billion. The share of gold has risen to nearly 10 percent, a target set in the middle of the past decade, raising market questions over whether the central bank will keep buying.

"We are buying metal and will continue to pursue this course," Ulyukayev told reporters on the fringes of the World Economic Forum in Davos.

"This is a course of asset diversification in a situation when investing in securities or deposits remains risky."

Ulyukayev also said the US dollar accounted for 46 percent of the currency portion of the central bank's reserves, and the euro 40.5 percent.

Sterling has a 9 percent share, the Canadian dollar 3 percent and the Australian dollar, added to Russia's reserves last year, at 2 percent.

Separately, Ulyukayev said that inflation could exceed 7 percent in February but should start to ease from March onwards. Consumer inflation reached 6.6 percent in 2012.

He saw no grounds for further monetary stimulus but left open the direction of the central bank's next interest-rate move. "It could be one way or the other," Ulyukayev told reporters.