Emergency services are currently dealing with the incident on the Dobbin Road, close to the Centra store.
A number of ambulance and fire crews are on the scene with police currently co-ordinating traffic.
The road is impassable and motorists are being turned around in both directions.
One eye-witness, speaking to Armagh I, said: “We have just been turned around by police – it looks really bad.
“There are two ambulance and two fire engines there, along with police.
“It looks like the accident happened on the way to Portadown; there are road workers and traffic lights in place on that part of the road at the minute so it’s all a little chaotic.
“I think it’s a case of advising drivers and letting them know to stay away as there are queues now forming.”
A police spokesperson said: “The Dobbin Road between Portadown and Armagh is currently closed due to a road traffic collision.
“Diversions are in place via Vicarage Road from both sides to avoid the area. Please drive carefully and keep speed down as Vicarage Road will have extra traffic at this time.”
There are no further details at this stage but please avoid the area this morning.