Two UN officials issued a statement Thursday expressing concern over the independence of Cambodia's judiciary, following the sacking of a judge from her position as chief of the Appeals Court.
Judge Ly Vuochleng was ousted by Royal Decree following allegations of bribe-taking.
"The replacement of the Appeal Court president was done at the request of the executive branch of government in contravention of the separation of executive and judicial powers specified in the constitution," wrote rights envoy Yash Ghai and legal expert Leandro Despouy in a joint statement.
Under Cambodian law, "judges, like all citizens, are entitled to a fair hearing and other guarantees of due process," they wrote.
Ly Vuochleng was replaced by Khmer Rouge tribunal judge You Bunleng, who was also placed on the Supreme council of the Magistracy along with three other new appointments.
You Bunleng's appointment "appears to have been made…at the request of the executive rather than in accordance with the law."
Prime Minister Hun Sen sits at the head of the executive branch, and Ghai has said in the past he controls all the decisions.
Cambodia's governance rests solely in Hun Sen's hands, to its detriment, Ghai has said.
Tribunal observers say the process has been bedeviled by leadership afraid to see government officials who were cadre of the Khmer Rouge face trial, while the judiciary in Cambodia is widely seen as corrupt and politicized.
Ghai and Despouy said they shared general UN concerns that You Bunleng's appointment could further cloud the process.