An emergency warning has been issued on Monday evening for a bushfire threatening lives and homes in Forrestfield, Kalamunda and Lesmurdie, in the Perth Hills.
The fire began in bushland near Falls Road in Lesmurdie Falls National Park, a popular hiking and sightseeing destination.
People in an area bounded by Yorna Road to the north, Ozone Terrace to the west, Orange Valley Road to the east and Falls Road to the south are being told they are in danger and need to act immediately to survive.
Aerial bombers are at the scene trying to contain the blaze.
The bushfire is moving in a north-easterly direction.
A watch and act alert has also been issued for a wider area east of the fire into suburban Lesmurdie and Kalamunda.
A bushfire advice alert has been declared for areas west of the fire, including Kalamunda, Forrestfield and Maida Vale.
It is not known at this stage how the fire began.