According to police, the omni bus hit the brick-laden truck from behind.
The driver of the bus, M.Chandran (38) from Theni, and a passenger, R.Palaniammal (64), died on the spot.
Fourteen people have been injured in the accident and admitted at the Mahatma Gandhi Memorial Government Hospital.
The police have filed a case and investigation is underway.
Details are awaited.
Police said despite warning, drivers overspeed leading to the accidents.