Police are investigating after a heavy vehicle carrying livestock rolled in Bathurst last night, resulting in the driver being injured and the euthanasia of hundreds of sheep.

About 6.30pm (Tuesday 28 April 2015), emergency services were called after the truck travelling west on the Mid Western Highway at Robin Hill left the road and rolled.

Emergency services were called and the driver, a 48-year-old man, was trapped in the cabin for two hours before being freed by Police Rescue.

He was treated at the scene for a head injury and fractures, before being airlifted to Royal North Shore Hospital where he remains in a critical condition.

Local Police were assisted by Police Rescue, Fire & Rescue NSW, State Emergency Service and Rescue HAZMAT. They cut access points to the four level trailer and extricated the sheep, carrying them to a nearby grassed area, where they were assessed by a local veterinarian who attended.

Under the veterinarian’s direction, about 400 of the 480 sheep on board were euthanized by police due to injury.

Officers attached to Chifley Local Area Command have commenced investigating the circumstances leading up to the crash and would like to speak to any witnesses.