Bushfires threaten homes across WA

Two firefighters have been hospitalised after suffering heat exhaustion while battling a bushfire in the southern Perth suburb of Wattleup.

Authorities are expected to launch an investigation amid confirmation that three separate blazes were deliberately lit about 3pm off Moylan Road.

The Wattleup blaze destroyed two sheds. Firefighters saved six homes on Henderson Street as the blaze destroyed 47ha of bushland.

North of Eneabba, firefighters battled a raging bushfire that included 18m high flames.

Residents in the area of Arrowsmith, Brand Highway and the Indian Ocean Drive intersection north of Eneabba were all on alert as the unpredictable fire burnt through 31,000ha.

The blaze was moving in a north easterly direction within the Shire of Irwin but did not damage any homes.

After it flared up earlier in the afternoon the fire had been contained by 7.30pm with no lives or homes under threat.

Firefighters on the scene had support from four dozers, three graders, five fixed wing water bombers and the Type 1 helicopter.

Department of Environment and Conservation and volunteer bush fire brigade crews are expected to work throughout the night to consolidate existing firebreaks and protect structures in the Indian Ocean Drive area along Brand Highway.