While Mishra's car in the convoy was allowed to pass, vehicles of other Left Front members, including Howrah Zilla Parishad opposition leader Aparna Purkait, were not, a senior police officer here said.
As a result, Purkait and others were forced to go back to Howrah city from where they had started.
Mishra, who left for Kolkata after visiting some relief camps and distributing relief materials, alleged that Trinamool Congress supporters had tried to stop him from visiting the camps in the flood-hit areas.
Left Front chairman Biman Bose in a statement said, "Earlier, West Bengal Chief Minister had publicly asked other political parties to refrain from undertaking relief work or distribute relief items. Today's attack on Surjyakanta Mishra is just an example of how cadres of ruling TMC are carrying out those orders."
Bose said the attack proved that the all-party meeting, convened by the state government and the chief minister, was nothing but a "publicity stunt".