Tanya Marie who was driving past at the time said something "blew and shot across the road".
She said it was a single car and didn't appear to be a crash.
The burnt out car on State Highway 5 at Waiotapu. Photo/ Supplied
Rotorua fire station officer Dean Irwin said the car was well alight when they arrived with one fire truck from Rotorua and the water tanker from Lake Okareka rural fire force.
Irwin said the cause of the fire was yet to be determined but it was a timely reminder for people to give their car a full service before going away on long drives at this time of year.