Firefighters battling bushfire in iconic Kings Park

But they say there is no threat to lives or homes from the blaze that broke out on Tuesday about 2.45pm AWST.

More than two dozen fire crews are on the scene and a bushfire advice is in place for people in an area west of the city.

"It is not contained or controlled (and) firefighters are on the scene, actively fighting the fire," the alert from the Department of Fire and Emergency Services says.

"Although there is no immediate danger you need to be aware and keep up to date in case the situation changes."

Local resident Gareth Hayes said ash was dropping around his house about two kilometres from the park.

"There helicopters buzzing about and I can see a big plume of smoke drifting west away from the park."

At about 400 hectares and 10km around, Kings Park is one of the world's largest inner city parks and a popular tourist spot.

It is located immediately to the west of the Perth CBD on Mount Eliza and is a mixture of bushland, botanic gardens and grassed parklands.