A two-year-old girl, who was a passenger in a car involved in a fatal crash south-east of Perth yesterday, has died in hospital.

A 60-year-old female American tourist was killed yesterday in the head-on collision on Albany Highway in Bedfordale, 40km from Perth.

A 61-year-old man and a 21-year-old woman in the same car were also seriously injured.

The driver of the other car, a 27-year-old man and his three passengers, including the two-year-old girl from Katanning, were also seriously injured.

The girl spent the night in Princess Margaret Hospital but died this morning.

Police are asking anyone who witnessed the crash to contact them.