The agency told motorists to merge to pass the wreckage and to expect delays.
Traffic had already started to pile up over 2km back only 10 minutes after the fire was reported to emergency services.
A passing motorist told the Herald she saw firefighters battling the blaze.
“I was driving from Panmure when I saw it. I just saw smoke. We thought it was from one of the houses - but by the time we got up to it, it was a car,” she said.
“We saw firefighters putting it out - and police there too.
“Traffic was crawling. The smoke has gone down now, so the traffic is calm now.”
Fire and Emergency NZ received multiple calls to the fire about 2.25pm.
The driver wasn’t with the car and hasn’t been found, a Fire and Emergency spokeswoman said.
The car was well involved in flames when firefighters first arrived at the scene, she said.