Firefighters are mopping up after a blaze at a century old house in West Perth.

Emergency crews were called to the Florence Street home just before midday when smoke was seen billowing from the property.

Two men, aged in their twenties, were inside the house sleeping but escaped unhurt.

Firefighters are assessing the risk of asbestos material from the house and have set up an exclusion zone in the street.

The cause of the blaze is being investigated.