Top officials in Cambodia are involved in illegal logging and helping to strip the nation of its natural assets, an international watchdog has said.
Swathes of Cambodia's rainforests have been lost to logging
Global Witness claims that legitimate land concessions are being used as a cover for criminal activity.
The London-based organisation has also accused international donors of failing to act to stop the trade.
The Cambodian authorities, as well as officials named in the report, have dismissed the allegations.
Forestry Administration director Ty Sokhun, one of the officials accused, described Global Witness as "insane, unprofessional people" with no knowledge of forestry.
A company director also named in the report described the charges as "unacceptable".
Global Witness accuses ministers, business people and relatives closely linked to Prime Minister Hun Sen, as well as the military and police, of involvement in the alleged asset stripping.
The non-governmental organisation said that "legally dubious" permits for plantation developments and harvests are being handed out to a small group of people close to senior politicians.
Valuable, high-quality timber is being described as firewood to avoid detection and taxation, the group goes on.
"Logging is part of a massive asset stripping for the benefit of a small kleptocratic elite," Simon Taylor, Global Witness director, said.
"The forests of Cambodia have been ransacked over the past decade by this mafia with little or no benefit flowing down to the ordinary people," he added.
The 95-page report comes ahead of a meeting of international donors to discuss future aid to Cambodia.
"If Cambodia's donors want the country's natural resources to be managed in a way which benefits the Cambodian people, then they must confront the high-level corruption which allows [these groups] to operate," Mr Taylor said.
Global Witness used to act as the Cambodian government's official forestry monitor, but was expelled from the country a few years ago after relations between the two sides deteriorated.