Woman dies in Perth freeway bus crash

A woman has died after a coach bus crossed onto the wrong side of Perth's Kwinana Freeway and collided with her four-wheel drive.

A toddler in the woman's car was taken to Princess Margaret Hospital with non-life threatening injuries.

The bus driver, who is in his 60s, was taken to Peel Health Campus while a passenger in her 20s went to Fiona Stanley Hospital.

The TransWA bus was heading south on the Kwinana Freeway about 1.10pm when it crossed the median strip near Paganoni Road, Karnup into oncoming traffic.

The remaining 21 passengers were treated at the scene for minor injuries.

The freeway northbound remains closed at Mandjoogoordap Drive and is likely to remain closed for several hours.