Domestic demand from a fast-growing economy only adds to the problem, they say.

"As for the question that China's large demand for timber assists illegal logging and smuggling from Asia, this statement has no basis,"State Forestry Administration spokesman Cao Qingyao told a news conference.

"The Chinese government consistently upholds and puts in practice collective international responsibility, opposing and cracking down on illegal logging in illegal wood imports," Cao said. "We have very strict import controls."

Global Witness, a British-based non-governmental organisation, said last year China imported timber from Myanmar alone worth an estimated US$350 million, almost all of it illegal.

But the group conducted an investigation in May that showed Chinese checkpoints had been sealed to log transports from the former Burma, where years of military rule and ethnic unrest in remote mountain areas have lead to widescale forest clearances.

A report issued in March by the Centre for International Forestry Research and other groups found about 70 percent of all timber imported into China, now the largest consumer of wood from tropical developing countries, was converted into furniture, plywood and other processed products for export.

China accounted for over half the log exports from Papua New Guinea, Myanmar and Indonesia, the report said.

Cao said that over the next few years China's timber trade would be stable, with exports not exceeding imports, though that for certain products, like paper, there was still a lack of domestically sourced wood.