The attackers are said to be supporters of President Mahinda Rajapaksa who were putting up posters.
"You are one of them and we want to take you to the police. We are from the STF", one of the attackers told Ariyadasa before assaulting him with wooden poles after pointing a pistol at him in a mock execution.
The attackers fled when the neighbours arrived on the scene and found the victim in a critical situation.
They rushed him to the Deniyaya hospital from were he was transferred to the Matara hospital.
Chandrasekar said that both the Deniyaya police and the police post at the hospital refused to take down any complaints and it was alarming how supporters of a candidate can attack supporters of another and get away scot-free without being brought before the law.