The US can directly fund some of the Khmer Rouge tribunal, if the courts can clear themselves of corruption allegations, outgoing US ambassador Joseph Mussomeli said.

"I think we need to find from the Cambodian side a clear, firm commitment to get rid of corruption on the administrative side," Mussomeli said. "I think in Washington everybody now is very much looking forward to finding funding to help directly assist the tribunal, if we could just work this last thing out."

The tribunal has been hampered by allegations of kickbacks, corruption and mismanagement.

Donor countries to the tribunal are now considering whether to continue funding the courts, following fresh allegations of kickbacks made by Cambodian staff in June.

The Cambodian side has established a task force to deal with the allegations.