Terming the arrest as a "repressive measure" by the Tamil Nadu government, he said that "those arrested must be released".
"I don't think it is right (on the part of the government) to file cases after cases and to arrest Anbumani Ramadoss (son of S Ramodoss) for something he said long time back. I seek the release of Ramadoss on humanitarian grounds," he told reporters.
"I am worried Ramaodss has been imprisoned. PMK cadres should stop talking of opposition and other politicial parties in an inappropriate manner. Such actions will not help in finding a solution to the present situation," he said.
Ramadoss was arrested in Villupuram on April 30 while staging a protest.