The incident occurred this morning as BJP workers were assembling in front of the Sirkazhi taluk office to stage a demonstration against Viduthalai Chiruthaigal Katchi leader Thol Thirumavalavan's alleged remarks on Hindu temples, they said.
All of a sudden, VCK cadres who came there allegedly started hurling stones on the BJP members, injuring six of them, they added.
Twenty one members of the VCK have been arrested in this connection.
A large number of police personnel have been deployed in the town to prevent any untoward incident.