The Colombo- Avissawella Low Level Road has been blocked at Kotikawatte due to a protest, the Police Media Unit said.
The protest is carried out by a group demanding flood relief, the Unit also added.
The protesters accuse the government authorities of delaying relief for flood victims in the Colombo district.
Areas in and around Kotikawatte were severely affected by flood after South-west monsoon rains in May, during the past few years.