A WATCH and act alert has been issued for people on Toodyay Road, Fernie Road and Morangup Road in Morangup.
A fire is burning in bushland and private property on both sides of Toodyay Road.
The alert was given just before 1pm today.
Lives and homes may be under threat.
Toodyay Road is closed between Morangup Road and Fernie Road.
People are being told to avoid the area and be aware of fire and other emergency services personnel working on site.
Approximately 50 volunteer Bush Fire Service firefighters are on the scene, with aerial support assisting ground crews.
The cause of the fire is unknown.
People are asked to report any suspicious behaviour to Police Crime Stoppers on 1800 333 000.