They have warned that using such equipment incorrectly can cause “serious harm” and be “potentially fatal in the wrong hands”.
The medical device, which is used in life-threatening emergencies when people are in cardiac arrest, was taken from the scene of an incident in Union St West, Oldham, Greater Manchester at around 12.15am.
A defibrillator is a staple device carried by every NWAS emergency vehicle, but is different to those used in the community and requires proper training to use them.
A spokesperson for the service said: “These defibrillators are much larger than the community ones and those in public buildings, and special training is required to use them – as well as being an expensive and necessary piece of equipment for any ambulance crew, using them incorrectly can cause serious harm and they can be potentially fatal in the wrong hands.
“We urge whoever took it not to use it on anyone and to contact us on 0345 113 0099 to arrange its return.”
They asked anyone with information about the stolen defibrillator to call the same number.