Police are investigating a fatal crash in the city's west-end after a driver, apparently going the wrong way on the northbound 427, collided head-on with another vehicle on the eastbound QEW ramp to the 427.

The driver heading in the wrong direction has been taken to hospital with life-threatening injuries.

Two people in the other vehicle were pronounced dead at the scene with another taken to hospital with life-threatening injuries.

The collision happened just before 3 a.m. Sunday.

The eastbound QEW ramp to the northbound 427 was closed for the police investigation.

Although it's not known if alcohol was involved, police are investigating that possibility.