A cube van and an SUV have collided in the eastbound lanes of the Queensway nearest the Belfast Road overpass.
Emergency crews had to free one person from the wreckage.
Fire crews say diesel fuel is covering the outside lane for several hundred feet.
The eastbound Queensway has been reduced to one lane at the Belfast overpass while one westbound lane is closed due to debris.
Authorities say the gridlock on the highway will continue for several hours and that it is best to avoid the area if possible.
