The westbound route of the M27 at Portsmouth has now been reopened after an accident involving a lorry and two cars.
Traffic is moving slowly between Junction 12 with the M275 and Junction 11 for Fareham.
Motorists have been advised that they could face delays of up to one hour. Romanse has warned drivers not to use the motorway, with vehicles queueing as far back as the A3(M).
Two people have been suffered non-serious injuries in the incident, and are being taken to Queen Alexandra Hospital.
South Central Ambulance Service have sent two ambulances, a hazardous area response team and an air ambulance to the scene.
Diversions are currently in place via the A27, but there are tailbacks as far as the A2030 Eastern Road junction as a result.