"There was a lot of sparking coming from the car, I couldn't breathe because of the smoke," the motorist said.
They said they turned the engine off and moved into the back seat and waited for assistance from emergency services.
A large burn mark was left on the driver's side of the vehicle.
The incident happened about 1.30pm on State Highway 2 near Wairoa Pa Rd in Bethlehem.
However, just before 2pm, emergency crews had yet been able to approach the vehicles involved because of powerlines on both cars.
A Fire and Emergency spokeswoman said crews were waiting for power company staff to arrive to establish whether the powerlines were live.
She said it was not known whether those involved in the crash were injured; but said they remained inside the vehicles.
Ambulance staff were also unable to approach the cars because of the possible live powerlines.