This accident happened this afternoon, Monday, June 15, on the Rathfriland Road in Newry.
The collision took place at around 4.30 pm near Ashtree Cottages.
The Rathfriland Road remains closed as the police investigation into the collision continues.
The road is expected to remain closed for a number of hours.
Inspector Lynsey Barr has appealed to anyone who was travelling on the Rathfriland Road this afternoon and who witnessed the collision to contact police in Ardmore on 101.