Two fire engines were sent to the scene north of Junction 12 where a saloon car was on fire in a slip road at around 10.40am.
Pictures showed flames reaching into the middle lane of the northbound carriageway as thick black smoke poured out of the vehicle.
Two out four lanes were blocked while firefighters from Penkridge and Cannock used hose-reel jets to put out the blaze.
The two lanes and the Junction 12 northbound entry slip road remained closed at midday while the area was being cleaned up.
Highways England said slow traffic was passing the scene.
The car was gutted by the fire.