Russia must tighten controls on timber crossing its frontiers and take other steps to enforce the rules, it said, adding corruption by local officials was a big problem.

The WWF estimated at least 20 percent of timber logged in Russia was cut illegally or in violation of legislation due to bribery and a lack of funds to enforce controls in an area the size of Germany, the Netherlands and Belgium combined.

"Pristine forests in the Russian Far East are being illegally logged at an alarming rate to satisfy rising demand in China, South Korea and Japan," the organisation said in a statement.

Illegal timber sales were worth some $450 million a year, and two-thirds of this was earned abroad, it said.

"The illegal logging in the Russian Far East makes up approximately 1.5 million cubic metres of wood annually. It is a highly profitable activity for smugglers and the local mafia," the Swiss-based group quoted its Russian project manager, Anatoly Kotlobay, as saying.

It said it had documented cases of logging without permits, felling of protected tree species, use of fake documents, bribes and export without appropriate papers.

"In many cases, individuals and institutions charged with protecting these forest resources are implicated in the illegal trade," the WWF said.