Authorities say an Albuquerque ambulance worker catching some sleep in the back of his vehicle woke up to find himself the victim of a carjacking.

The ambulance was parked outside Lovelace Medical Centre in downtown Albuquerque, New Mexico, when a man and a woman took it at around 3am on Saturday. 

Police spokesman Elder Guevara says the employee was asleep in the vehicle's rear but the employee was able to jump out the rear doors as the ambulance slowed down at a junction during 50-mile police chase.

Officers then pursued the ambulance as it headed eastbound, and then westbound, on Interstate 40.

Police have not released the names of the suspects or the victim, who was uninjured.