Income Tax Department officials on Friday raided Tamil Nadu Health Minister C Vijayabaskar's residence here and premises of his associates, official said.
Raids were also underway at actor Sarathkumar's house, the senior IT official said on condition of anonymity.
The raids were being conducted in at least 20 places here and 11 other places in the rest of Tamil Nadu, the official added.
He said: "Trigger for raids at Vijayabaskar's residence is the money distributed to voters in RK Nagar constituency where bypoll is slated on April 12.
The officer said the Minister was on IT radar for the past one year in connection with his quarry business.