Lieutenant General Khieu Sopheak, spokesman for the Ministry of Interior, said he too had not seen or heard of the letter.
Lt Gen Sopheak said that NGOs who abide by the Constitution and law, and “as long…as they have registered with the government, they can do their duty.”
He also said that he was not aware of any provision preventing any NGO – foreign or local – from advocacy.
“I don’t think we have any provision like that.”
Yeng Virak, executive director of the Community Legal Education Center, a local legal aid organization, said he knew of no laws that would allow the government to stop foreign NGOs from advocacy work and that the very idea was problematic.
“Keat Chhon proposes, so he advocates, so he does advocacy work, too. That means everybody does advocacy, that means you want to influence the person who has influence to do something,” he said. “So I just cannot understand and I cannot accept it.”
Mr Virak said it made no sense to expect NGOs trying to help the country develop not to advocate.
“Advocacy is development work, so the government should be educated that advocacy is not a violent thing,” he said.
Brian Lund, East Asia regional director for Oxfam, agreed that advocacy was inextricably linked with the work the groups do.
“In a healthy democracy it’s quite important that civil society groups have a place to speak out on social issues,” he said. And whatever form that advocacy takes, he added, “it’s a necessary space in a democracy for civil society.”
The news of Mr Chhon’s letter to the prime minister comes amid the drafting of a new law that aims to regulate the country’s associations and NGOs. But hundreds of those NGOs say the law as written would give the government a near-free hand to stifle its critics.