Ontario's police watchdog is investigating after a Peel police officer was hit by a police cruiser Sunday morning.

The Special Investigations Unit says the officer was off duty on a paid duty assignment at Eglinton Avenue West and Erin Centre Boulevard in Mississauga.

The SIU says a police cruiser responding to a call about a break and enter struck the officer, who was rushed to hospital with serious injuries.

The Special Investigations Unit is automatically called in where police are involved in cases that result in death or serious injury.