A police spokeswoman said they were alerted to a car fire on Bledisloe St (State Highway 83) in Kurow at 2.45pm yesterday.
All occupants of the car were reported to be out of the car safely and there was no indication the car had been involved in a crash.
The fire was extinguished and the spokeswoman said the car was towed about 5.40pm.
A witness staying at a nearby camping ground said he was unloading his caravan when he heard "an almighty boom" followed by sirens wailing.
The flaming vehicle, a Toyota, was surrounded by "black smoke everywhere".
"We raced up there and the car was fully engulfed by that stage."
A Fire and Emergency New Zealand spokesman said crews from Kurow and Duntroon responded.
When they arrived, two volunteer firefighters in breathing apparatus were working to extinguish the blaze and the road was closed temporarily.
