The opposition Cambodia National Rescue Party (CNRP) has planned a mass gathering of its supporters in the capital Friday, the same day that its deputy leader, Kem Sokha, is due to appear in court.
A CNRP official said the gathering had been approved by the municipality, but officials also said they plan to erect barriers to prevent opposition supporters marching on the city center.
Morn Phalla, director of the opposition CNRP's executive committee, said authorities had stressed that the meeting could go ahead if traffic was not disrupted and security forces policing the gathering were not abused.
Mean Chanyada, a City Hall spokesman, said the number of people due to attend was "not a concern," but cautioned CNRP supporters against "gathering on the sidewalk."
Am Sam Ath, technical supervisor at local rights group Licadho, said traffic jams were more likely to be caused by the "complete road blockades by the authorities."
Sokha is due in court Friday for questioning after missing a previous court date, where he was due to be questioned in a sex scandal case.
This report was produced in collaboration with VOA's Khmer Service.