Residents in Western Australia have been forced to flee nearly 40 homes due to wildfires that have injured three people.

Hundreds of firefighters were attempting on Wednesday to bring the blazes near the wheat and sheep-farming town of Toodyay, 80km from Perth, under control.

There are fears that the nearby town of Badgingarra will also be threatened.

Authorities believe that the fires were started by fallen electricity cables, assisted by high summer temperatures and strong winds.

"It's a devastating fire with great destruction," Colin Barnett, the Western Australia state premier, said.

Officials have already given "catastrophic" warning signals for fires in three states this summer and are preparing for an arduous bushfire season.

The "catastrophic" warning signal was developed after so-called Black Saturday in February 2009, when 173 people were killied in wildfires and thousands of homes were destroyed in Victoria state.

Typically bushfires are a threat from October to March, when there are high temperatures and low humidity levels.

Lightning strikes often start fires in the dry environment.