The flood, caused by rising sea levels, swamped the road between the Industrial Ring Junction and Nang Linchi Intersection.
Bang Phongphang Station Superintendent Pol Colonel Itthipol Pongthorn said traffic was paralysed after water overflowed the sandbag barrier at Soi Rama III 52.
He added that the police are cooperating with Yannawa district officials to mitigate the flood impact on motorists.
"We would like to ask motorists to avoid using Rama III Road for a while because we are not sure when the situation will be resolved," he said.