For some 15 years councilors have been forced to work out of a small area in a villager’s home.
The Sala Kam Reuk commune chief said the commune office is markedly busier than is was under the guardianship of his predecessor.
The opposition Cambodia National Rescue Party won 489 out of 1,646 commune chief positions in the June 4 election.
The letters ordered the groups to halt their activities and said the Situation Room was an unregistered organization and in breach of the law.
The political parties law was amended before the election to block people with criminal records from leading political parties.
The ruling Cambodian People’s Party won 1,156 seats to the CNRP’s 489, with one seat also won by the Khmer National United Party.
Morn Phalla told VOA Khmer he was unaware of any violence being reported during the election campaign, which he organized for the opposition.
The prime minister slammed the Situation Room, a collection of election monitoring NGOs, for painting the Cambodian political landscape as “gloomy”.
Sin Chanpeourozet, a young female CNRP activist, was one of seven opposition councilors elected in the commune.
It went on to threaten legal action against the CNRP for “slander or false statement”.
Analysts said the comments were an attempt to gain support ahead of a general election next year.
Phouk Prathna, 25, is one of the youngest local councilors elected to run a local authority in Bavet commune, Svay Rieng province.