Two cars were found well alight on the westbound side of the road, Shropshire Fire and Rescue Service said.
Shropshire's Police Operational Patrol Unit said at about 7.40pm that the road will be closed all evening tonight due to the crash.
"A5, Emstrey roundabout, west bound to Dobbies roundabout will be closed all evening tonight for emergency repairs following a road traffic collision," the team said.
At about 6pm tonight, Shropshire Fire and Rescue Service were called to the A5 westbound between Emstrey and Bayston Hill at Shrewsbury.
A fire service spokesman said: "The road is closed to the public going from Emstrey to Bayston Hill westbound.
"Three fire appliances were mobilised from Shrewsbury to deal with two cars well alight on the carriageway."
An operations officer was in attendance and crews used breathing apparatus, a covering jet and a hosereel jet to extinguish the fires.
Crews managed to extinguish the fire by 6.40pm.