MGR AIADMK Kancheepuram District secretary Jayagopal and three others were killed when the car they were travelling in collided with a lorry near Namakkal early on Wednesday morning.
Three others in the car were injured and have been hospitalised, police said.
They were proceeding from Pennagaram after campaigning for the March 27 bypolls there, to the Lord Iyyappa temple at Sabarimala in Kerala when the mishap occurred.