The Ministry of Foreign Affairs has issued an order banning Cambodian embassies the authority to issue visas for UN human rights envoy Yash Ghai without prior approval.
Ghai has had an increasingly cantankerous relationship with the government, especially with Prime Minister Hun Sun, following his strident criticism of Cambodia's poor human rights record and the concentration of power in the hands of the premier.
The visa restriction comes days ahead of Ghai's expected rights report to the International Human Rights Council in Geneva.
"Any visa application to Mr. Yash Ghai has to be approved from the Ministry of Foreign Affairs in advance, even if he's holding any kind of passport," the order says.
Christopher Peschoux, director of the Human Rights Office in Cambodia, said he would seek clarification on whether this policy was wider reaching or applicable only to Ghai.