The M1 motorway has been closed near Lurgan.
The Air Ambulance has been tasked to the scene.
The PSNI is dealing with what has been described as a “serious road traffic collision” on the Belfast-bound lane.
The motorway is closed in both directions between Junctions 9 and 10, Moira and Lurgan.
There are long tailbacks in the area and motorists should be advised of delays.
Police are asking for drivers to be patient.
There are no further details at this stage.