"DMK chief's health condition is stable. He is well. A medical team is attending on him. Me and deputy chief minister O Panneerselvam along with DMK party working president M K Stalin and Rajya Sabha MP Kanimozhi visited him in person," Palaniswami was quoted by PTI as saying.
State ministers, including Law Minister C Ve Shanmugam, accompanied the chief minister to the hospital.
Karunanidhi is being treated at the ICU for the third consecutive day. Concerned DMK workers continued to swarm the hospital premises to know about the former Tamil Nadu chief minister's health.
The Chennai Police had asked them to avoid crowding the area and party leader M K Stalin appealed for calm and cooperation with police in maintaining law and order.
A medical bulletin released by the hospital on Karunanidhi's health last night said: "There was a transient setback in the clinical condition of DMK president M Karunanidhi. With active medical support, his vital signs are normalising. He continues to be closely monitored and treated by the panel of expert doctors."
Police had late last night resorted to a mild baton charge as cadres did not disperse from the area to make way for DMK leaders to leave the hospital at upscale Alwarpet.
Vice President Venkaiah Naidu on Sunday visited Karunanidhi along with Tamil Nadu governor Banwari Lal Purohit. The DMK later released a photograph showing Naidu standing beside the 94-year-old leader in his hospital bed.
Karunanidhi was admitted to the hospital in the early hours of Saturday after his blood pressure dropped.
On July 18, he had undergone a procedure at the same hospital for replacement of a tracheostomy tube to help him breathe normally.
(With inputs from agencies)