"This kind of remark will badly hurt him in Tamil Nadu", Swamy said.
Writing for Tamil magazine Ananda Vikatan, the actor has said that Hindus can not claim that extremism doesn't exist among them anymore.
He wrote that right-wing Hindus have realised that their attempts of using debates are not working and now they have resorted to violence.
"In the past Hindu right-wing groups would not indulge in violence, but they used to hold dialogues with the opposition parties to win arguments. But now they resort to violence", Haasan wrote in his column in a popular Tamil weekly news magazine.
Haasan further wrote, "The right wing can not challenge talk of Hindu terrorists because terror has spread into their camp as well". "Such terror activities are not going to help them in way", he added.
Haasan, who met Kerala chief minister Pinarayi Vijayan recently, also answered a question posed by the Marxist leader, who asked what the actor felt about "Hindutva forces weakening Dravidian culture through slow intrusion".
Haasan, who has been hinting at entering politics, is expected to make a major announcement on November 7.
The actor's comments have drawn flak from the BJP and RSS members on social media.
He was seen to meet Kerala chief minister Pinarayi Vijayan and Delhi chief minister Arvind Kejriwal weeks ago.
"World over, there is a move towards fascism and a leaning toward the right-wing".
Even the Shiv Sena, which now has a blow hot, blow cold relationship with the BJP, slammed Kamal Haasan, who recently announced that he was ready to join politics but has refused to divulge much about his plans so far, for his article.
"With his myopic and brazen comments on the so called Hindu terror, Kamal Haasan has signalled that he has arrived on political scene as a fringe element", Mr Rao said. "It was done by the former home minister P Chidambaram and Congress leader Sushil Kumar Shindey saying it on the floor of Parliament that there is Hindu terror in this country", BJP's national spokesperson GVL Narasimha Rao said.