A post mortem has confirmed the cause of death overnight of a Christchurch man

Police have found 30-year-old Steffan Pearce-Loe died in hospital hours after he was struck by a car in Dallington on Thursday morning.

He was believed to be walking his two dogs, just north of the Gayhurst Bridge over the Avon River when he was struck by a passing motorist.

Detective Senior Sergeant Greg Cottam says it is possible the driver may have thought they had hit a dog or another object, and is urging them to come forward.

Police are reviewing CCTV footage, and are working to establish what type of vehicle the car parts located at the scene came from.