PHNOM PENH , Cambodia ( CNN ) -- A joint Cambodian-United Nations court , currently trying five former members of the ultra-Maoist Khmer Rouge group on war crimes charges , is itself facing allegations of corruption and bribery . Cambodia 's Minister of Information Khieu Kanharith says no proof of kickbacks or corruption has been found . Two employees of the court 's Office of Administration told CNN of an ongoing kickback scheme involving Cambodian staff . The staffers asked their identities be protected out of fear of retribution to themselves and their families . `` We are talking about 30 to 40 or even a little bit more ... a month , '' said one employee , referring to the total amount allegedly taken from employees . `` Thousand dollars . Thirty or 40,000 dollars a month . '' Cambodian staff at the office , they say , are forced to hand the money over -- a chunk of their salaries -- and the funds go to an official . `` They are supposed to pay a certain amount ( of ) money -- a certain percentage , '' the employee said . `` So every month , they have to put it in an envelope -- and give it to ... each section has one person go around to collect it ... the money is in cash , in U.S . dollars . '' There is no suggestion that the court 's judges or lawyers -- who are hearing and presenting the case against the former Khmer Rouge leaders -- are involved in the alleged corruption . The Cambodian government told CNN a senior Cambodian court official was investigated for corruption , but was exonerated . `` They told me they can not find any proof of kick-back or corruption , '' said Khieu Kanharith , government information minister . `` If you want the court -- the trial -- to go ahead , separate the two cases . '' However , a defense attorney for one of the defendants said the trial and the allegations of corruption are inextricably linked . `` What 's really disturbing is that by the time the judges make their decision , every piece of evidence , every bit that they look at and evaluate and deliberate on , will have passed through the office of administration and will have literally passed through the hands of people who we say have dirty hands , '' said Andrew Ianuzzi , a consultant for defendant Nuon Chea 's legal team . Defense attorneys say they plan to bring up the corruption allegations during the trial in an effort to discredit the court . The Cambodian government refused United Nations requests for an independent international war crimes trial for the Khmer Rouge defendants , agreeing only to a joint trial where the government participates along with the international judges . Watch a report on the trial a Khmer Rouge torture camp commandant » . Prosecutors are attempting to prove that the five defendants played a significant role in the deaths of as many as two million Cambodians during Khmer Rouge rule of the country from 1975 to 1979 . The trial has already cost $ 56 million , more than $ 10 million per defendant . But the court has asked for another $ 50 million to carry it through the end of 2009 . The total could go higher if the trial continues into 2010 . The United Nations says its internal affairs body -- the Office of Internal Oversight Services ( OIOS ) -- is investigating the corruption allegations within the court , but wo n't elaborate . `` This matter has been under investigation by OIOS , whose work is confidential , '' the United Nations said in a statement . `` The result of the probe will be submitted to the Cambodian government for further action . '' In a letter sent to attorneys for the trial defendants , Sean Visoth , the head of the court 's Office of Administration , writes that his office has `` never tolerated any kind of corruption or malpractice . '' Visoth says the court now has an anonymous `` complaint mechanism '' in place . Meanwhile , however , independent trial monitors say they believe a culture of fear prevents other current and employees from coming forward . `` At the court , I have heard people express concerns about loss of their job , repercussions or retaliations against their families , and also some possibility of physical fears , '' said Heather Ryan , a Khmer Rouge trial monitor . The employees spoke out , saying they were fully aware of the risk . `` To me , it is really sick . How can you take money from people each month and look people in the eye and say , 'Oh , I do n't know anything about it ? ' '' one employee asked .
Joint Cambodian-U.N. court is facing allegations of corruption and bribery . Court is trying five former members of Khmer Rouge group on war crimes charges . Staff are allegedly forced to hand part of salaries over , with funds going to an official . Defense attorneys say they plan to try to discredit the court with the allegations .