Narayandas, a construction worker who was waiting for a bus, was hit by the ambulance while the vehicle attempted to overtake a bus at Nilambur.
Passersby, who gathered there, noticed a body in the ambulance and immediately informed the police.
However, the ambulance driver, who has been taken into custody by police, claimed that the person in the ambulance was alive at the time of accident.
The person was being taken to Tirupur from a hospital here when the mishap occurred and under its impact died, the driver claimed.