UPDATE: Homes reportedly lost in bushfire burning in Western Australia's south-west

Firefighters say at least three homes have been lost to a dangerous bushfire burning in south-western Western Australia.

An emergency bushfire warning was earlier issued for the town of Waroona.

The Department of Fire and Emergency Services (DFES) has urged residents not to leave as doing so may be deadly, with the fire burning out of control within the town after breaching containment lines.

Residents at risk should visit the DFES website or call 13 DFES (13 3337) for the latest bushfire updates.

Those in an area bounded by McDowell Street, South West Highway, McLartey Street and Paganini Road are urged to take shelter and protect themselves with appropriate fire-safe clothing.

If their home catches fire, residents should flee to an area that has already been burnt.

An emergency relocation point has been set up at the Harvey Town Hall, located on the corner of Young Street and Uduk Street in Harvey.

The fire is believed to have been started by lightning and at least 325 hectares of bushland have been burnt.

Strong, gusty winds are fanning embers, with spot fires starting up to 400m ahead of the fire.

An earlier watch and act alert for the blaze was upgraded after the blaze intensified.

The DFES said 10 power poles have been destroyed and at least 28 homes are without power.

At least 150 firefighters are battling the fire.