The A11 at the Stag roundabout in Attleborough is closed in both directions following an accident involving an HGV and a minibus.
Norfolk Police received a call at 3.10pm alerting them to the incident.
It is thought the HGV, found on its side, had gone across both carriageways. A minibus was also involved in the collision, the police later confirmed.
Nobody has been injured in this collision, however, both carriageways remains closed whilst emergency services are in attendance.
Damage has been caused to the central reservation and the road may be closed for some time.
Diversions have been put in place whilst an investigation is carried out, and motorists are being urged to find alternative routes where possible.
Witnesses are asked to call Norfolk Police on 101 quoting reference 271 of Wednesday 28 June 2017.
Two fire crews from Attleborough and Wymondham were also dispatched to the scene.