Police are seeking information about a crash near Donnybrook which killed two women yesterday afternoon.

A Kia Rio Hatchback collided head on with a Subaru Forrester on the South Western Highway, near Knights Road in Argyle at about 2.35pm.

Both drivers, a 47-year-old woman from the Kia Rio and a 23-year-old woman from the Subaru, died at the scene.

A 23-year-old passenger of the Subaru was taken to hospital with serious injuries.

Anyone with dashcam footage or who witnessed the crash is urged to contact Crime Stoppers on 1800 333 000.

Meanwhile, Forrest Highway and South Western Highway have now been reopened to traffic after the area was blanketed with thick smoke this morning.

Motorists are still being advised to drive with caution in the area.