Three people have been injured, one rushed to hospital with life-threatening injuries, after two cars collided along Forrest Highway in West Pinjarra, south of Perth, on Thursday evening.

About 6.40pm, a white Mitsubishi Pajero travelling south on Forrest Highway and a white Hyundai i30 turning right from Greenlands Road onto Forrest Highway were involved in a collision, causing the Mitsubishi to roll.

A male passenger of the Mitsubishi sustained life-threatening injuries and was rushed to Royal Perth Hospital for medical treatment.

The 43-year-old male driver of the same car was conveyed to Peel Health Campus as a precaution.