A shed, potentially two, are on fire next to a home in Erskine.
It is understood the sheds are not attached to the Pennington Gardens house.
A DFES spokesperson said the fire is not believed to be suspicious.
The spokesperson said it was unclear what was in the shed.
"The fire is under control but emergency services will be on the scene for at least another half an hour," the spokesperson said.
Four crews including Mandurah career firefighters and Falcon Volunteer Fire and Rescue are at the scene.
Police are encouraging residents and drivers to avoid the area and keep windows and doors closed.