The collision, involving a lorry, a silver Skoda Fabia and a bronze coloured Ford Focus, occurred at around 2.45pm on the north bound carriageway at the Moneymore Road junction.
The man and woman were travelling in the Skoda vehicle.
It is understood the elderly man died at the scene while the woman died in hospital a short time later.
Officers from the PSNI’s Collision Investigation Unit are investigating and would ask any witnesses or anyone with dash-cam footage which could assist them with their enquiries to contact them on 101 quoting reference number 731 12/10/18.
The A1 remains closed between Loughbrickland and Newry at this time.