The fire started yesterday in the Great Southern Region, south-east of Perth, and destroyed two houses and injured one woman, burning her face and hands as she fought the blaze. The injuries were not serious and she is being treated at a local hospital.

The fire also caused other significant property, crop and livestock losses and cut power to up to 40 homes and businesses.

The fire started about midday on a property near the border of Wickepin and Dumbleyung shires. With 35C temperatures and 45kmh winds gusting up to 65kmh, the fire quickly raced towards the Kukerin town site, burning down two houses, killing livestock and destroying crops.

A Fire & Emergency Services Authority spokesman said last night the fast-moving fire had overwhelmed local resources, burning 4500ha and was yet to be brought under control.

Western Power spokesman Peter Winner said an inquiry into the latest fire was underway and the corporation was aware of claims the fire had been started by a pole. He said crews would arrive in the area this morning and workers would begin repairs to at least 60 poles destroyed in the fire.

"Western Power has initiated a full investigation into the possible cause of the fire," Winner was reported as saying by ABC regional radio.

"Western Power will work closely with the other authorities and agencies which may be doing their investigations into the cause of the fire."

Earlier this week the corporation had announced it was investigating ways to reduce fire risks on Western Australia's electricity network.

Replacing wooden power poles with steel and concrete was one of the measures being considered in the $28 million study.

Winner told ABC Radio that wooden power poles could be a fire hazard.

"If you have pole top fires, for example, the pole can burn and that can lead to other types of fires, they also get damaged if there are fires for whatever reason," he said.

"There are quite a number of bushfires through the summer and Western Power loses hundreds of power poles every year from bushfires."

Western Power's fire safety has been under scrutiny since an independent report earlier this year found sparks from a Western Power pole ignited a bushfire near the Great Southern town of Tenterden last December, killing two women.