The group says land marked for their relocation lacks the infrastructure to support them.
Rhona Smith also calls for an end to pre-trial detention at the end of her sixth visit to Cambodia.
But former CNRP leader Sam Rainsy says the move will come in December in response to international pressure.
After trying to petition at cabinet offices and government ministries, they are turned away by police.
Meanwhile, villagers attempting to present petitions in land-dispute cases are held and questioned by police.
At least 13 reporters have been murdered in the country since 1994, with nearly no convictions.
Rights group says juveniles, pregnant mothers, babies especially at risk in harsh living conditions.
Logs are now sent by night across the border to Vietnam in specially modified vehicles, a local source says.
Stung Treng officials have yet to rebuild roads, schools, and health clinics, they say.
But NGOs and legal experts say more must be done to restore judicial integrity and independence.
The former president of the opposition CNRP is being held under tight restrictions in house arrest while awaiting trial.
He sends condolences to the family of CNRP lawmaker Cheam Channy, who died of cancer on Oct. 25.
Impact from Laos’ Don Sahong Dam felt downstream in Cambodia.
NGOs say authorities discouraged celebrations amid calls to reconvene the agreement’s signatories.
The protests come weeks after the EU said it will drop Cambodia’s preferential trade status over rights abuses.
The Inter-Parliamentary Union also demands to meet with opposition chief Kem Sokha under house arrest.
The EU has threatened Cambodia with a loss of trade status over rigged election, rights violations.