The driver of a lorry with a light coloured cab and low loader stole a digger from a site at Beechwood Avenue Moira around 6am on Tuesday morning.
The vehicle is believed to have made off in the direction of the Moira Roundabout or possibly headed towards Hillsborough.
The vehicle is also described as one using orange hazard lights.
The digger itself which is mostly yellow in colour with a faded green coloured cab on board.
The model is a YANMAR V105 with rubber tracks and has A.G.Wilson on the body.
Any sightings of the vehicles matching the description should be reported to police. They can be contacted on 0845 6008000 or ring Crimestoppers which is 0800 555111.