Perth fires may have been deliberately lit

A string of bushfires in Perth's southern suburbs are being treated as suspicious.

The fires started mid-afternoon on Tuesday in the eastern part of Baldivis and prompted an emergency warning for residents as they were threatening lives and homes.

Firefighters worked through the night to contain the blazes and bring them under control.

The fires are currently stationary but a watch and act warning remains in place as high temperatures and gusty variable winds are forecast for Wednesday.

Another fire in the neighbouring suburb of Wellard that began around the same time has been extinguished.