The mishap occurred late last night when the bus bound for Kumbakonam collided with the lorry at Vallam.
The deceased included drivers of both the vehicles, they said.
Twenty-three persons, who sustained injuries in the accident were undergoing treatment at the government medical college hospital at Thanjavur.
Expressing grief, Chief Minister K Palaniswami said in a release at Chennai today that he had directed two ministers to visit the injured.
"I express my deep condolences to the families of the deceased. I have directed Agriculture minister R Doraikkannu and Transport minister M R Vijayabhaskar to visit the injured," he said.
Palaniswami said orders have been issued to release Rs one lakh each to the next of kin of the deceased and Rs 50,000 each to the injured from the chief minister's relief fund.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)