Ontario has a new police services act, as a bill that dismantled some changes by the previous Liberal government passed today.

The new law narrows the scope of mandatory investigations carried out by the province's primary police watchdog.

The Special Investigations Unit's mandate had been to investigate circumstances involving police and civilians that have resulted in serious injury, death or allegations of sexual assault.

Now, investigations will be limited to when police use of force results in serious injury or death, as well as when an officer has shot at a person or if there is a reported sexual assault, and would have to wrap up investigations within 120 days.

The government said the previous rules had the SIU investigating suicides, or if people died after a medical incident, instead of just suspected criminal activity.

Critics have called the law a capitulation to police unions, but Attorney General Caroline Mulroney says under the Liberals the pendulum had swung too far one way, and this law restores a balance.