The Enforcement Directorate (ED) on Wednesday arrested Tamil Nadu Electricity Minister V Senthil Balaji under the Prevention of Money Laundering Act (PMLA), official sources said.

He was arrested after a long session of questioning, they said, even as the minister was admitted to a city government hospital after he complained of uneasiness.

He is likely to produced before a special court later where the agency will seek his custody.

The agency had launched multi-city searches in the state on Tuesday at the premises linked to the DMK's Karur strongman as part of the probe into money laundering.

The action came months after the Supreme Court allowed a police and ED probe into an alleged cash for jobs scam against him.

Earlier, he was hospitalised after he complained of uneasiness, DMK leaders said. State Minister P K Sekar Babu claimed there were 'symptoms' that Balaji has been 'tortured.'

TV visuals showed Balaji being uneasy while being brought to the Government Medical College, Omandurar Government Estate in the city.

"He is in the ICU. He was in an unconscious state and did not respond when he called him by his name. He is under observation... there is a swelling near his ear, doctors say there is variation in his ECG (electrocardiogram)... these are symptoms of torture," Babu told reporters.

Law minister S Reghupathy, who visited the hospital, questioned the need for the ED raids at Balaji's house running non-stop for hours.

TN minister Udhayanidhi Stalin was among the cabinet ministers who visited the hospital. Meanwhile, central paramilitary personnel were posted at the hospital.

The ED had launched searches at locations linked to Balaji at Chennai, Karur and Erode on Tuesday as part of probe into money laundering. Balaji was earlier with the AIADMK and had been Transport Minister in the late Jayalalithaa-led Cabinet.