Based on a two-year investigation, the London-based independent research group identifies a 'kleptocratic elite' linked to Hun Sen, his top forestry officials and personal army bodyguard.

The report names the syndicate as the Seng Keang Company, saying it is run by Hun Sen's first cousin Dy Chouch and the cousin's ex-wife and business partner, Seng Keang. Seng Keang is a friend of Hun Sen's wife.

The third key member of the syndicate is named as Khun Thong, brother-in-law of Hun Sen's forestry minister and father-in-law of his director-general in Cambodia's forest administration.

The syndicate's operations are supervised by Seng Keang's brother, who is an officer in the Cambodian army's elite Brigade 70, a 6,000-strong unit that serves as the prime minister's bodyguard.

The brigade organises transport and smuggling of the illegal timber for the syndicate and other companies, the report notes.

'Brigade 70's prominent role in timber trafficking and smuggling, as with elite families' dominance of illegal logging, reflects a wider consolidation of power in Cambodia by Hun Sen and his allies,' the 96-page report says.

Based on photographic evidence of logging camps, timber factories and smuggling operations, as well as business documentation, Global Witness is demanding urgent action from the Cambodian judiciary and international donors.

The international community still pumps US$600 million a year into the Cambodian economy - the equivalent of half the national budget.

Donors are due to meet later this month and Global Witness is seeking to force tough action after years of foot-dragging in the face of a worsening problem.

'Despite the huge amount of aid flowing into the country, the political culture of corruption and impunity means that Cambodians are still among the world's poorest people,' Global Witness director Simon Taylor said.

'When are donors going to start addressing the asset-stripping, mafioso behaviour of the current regime?'

The report states that some donors are wary of pulling out, fearing it will push Cambodia closer to China, which has deepened trade and diplomatic ties with Phnom Penh in recent years.

Hun Sen moved to ease international concern by personally announcing the 2002 logging moratorium. Companies get around it by exploiting so-called economic land concessions and rights to rubber plantations, the study notes. The Seng Keang operation has used rubber and economic concessions in Prey Long to destroy significant tracts of the largest remaining evergreen forest in mainland Southeast Asia.

The syndicate is now cutting and smuggling large trees worth an estimated US$13 million a year from the Prey Long forest.

The report also highlights extensive discrepancies between figures showing Cambodia's exports of sawn timber and plywood and the mainland's imports from Cambodia.

Cambodia officially recorded no exports of sawn wood to anywhere between 2000 and 2004, in keeping with the moratorium.

Beijing, meanwhile, declared regular sawn wood imports of US$34 million between 2003 and this year. Cambodia has yet to publish figures for the past two years.

Cambodian wood has also surfaced in Australia, Singapore, Taiwan and Vietnam, the report notes. Global Witness has been researching Cambodia's timber industry since 1995.

In 1999, Hun Sen's government appointed the group as an independent monitor to ease international concerns, before scrapping its involvement in 2003.

The group repeatedly but unsuccessfully sought input from the government and syndicate members before producing its latest study.