The Asian Human Rights Commission called on the government Monday to investigate allegations that police prevented villagers from attending a public forum in Ratanakkiri province in late November.
"The police set up a roadblock to prevent the organizers from entering the place so that the forum was not held," the Commission said in a statement.
Villagers had wanted to meet over alleged land grabs in their area.
The Commission said a police roadblock was a suppression of the right to the freedom of assembly guaranteed by the constitution.
It urged concerned citizens to send a request to Cambodia's top officials to punish the police in charge and to take "effective measures to prevent such suppression in the future."