The Air Ambulance was called to deal with a very ‘serious’ two-vehicle crash near Portadown this morning.
It is understood there appeared to be a head-on collision at the Carn slipway onto the Northway.
Police have sealed off the road and emergency services are at the scene.
Police have asked drivers to avoid the area.
Sinn Fein Cllr Paul Duffy said he had been speaking to senior police officer who had described it as a very serious crash and the road could be closed for most of the day.
Already rush hour traffic caught up in the incident describe being in a ‘car park’.
A PSNI statement said: “Please avoid the area at present and take care, traffic is likely to be heavy in and around the town centre due to this.
The PSNI said it is ‘attending two vehicle road traffic collision on A3 Northway Portadown The road is closed at the turnoff at the junction with Seagoe Road, please seek alternative routes’.
Traffic around Rushmere and Portadown centre is likely to be affected.