Seven emergency-level blazes have destroyed homes and torn through bushland, rural properties and suburbs on Perth's fringes in the past three days.
Authorities confirmed on Saturday that two more homes were lost while crews battled a fire at Keysbrook, south of Perth.
The two properties lost were believed to be empty at the time.
Incident controller with the Department of Fire and Emergency Services, Russell Wells told reporters strong winds were creating challenging conditions.
"Our concern would be that, you know, should those easterlies pick up, and carry burning material across our containment lines, then potentially we could see a break out of the fire," he said.
The fire at Keysbrook is currently contained.
Mr Wells said crews were being rotated to provide relief.
"We're rotating crews through and make sure they get a bit of rest before they come back," he said.
"We're bolstering resources into this evening."
Difficult terrain and homes spread out over a wide area were proving challenging for ground crews, with aerial assets used to spot fires and determine the best place to deploy resources.
Mr Wells said the main focus is preventing more fires from starting.
"So the big effort really today, is mopping up, and anything that's burning within sort of 20 to 50 meters of the fire perimeter, they're trying to extinguish it fully and they'll be continuing to do that overnight into tomorrow," he said.
Mr Wells said the wind was the main concern with the rate of the fire spreading by two kilometres per hour on Friday.
The weather bureau issued an extreme fire danger warning for the Burrup district, north west of Karratha on Saturday morning.
"Fresh west to northwest winds and hot conditions will lead to elevated fire dangers," the warning read.
 A strong wind warning is in place for coastal Pilbara, Perth, Bunbury, and Leeuwin.
Heatwave conditions in some parts of the state are waning, with the worst of the extreme heat now pushing into the NT.
But the weather bureau says there will still be severe heatwave warnings in place for WA for a while to come.
"Severe heatwave conditions over much of northern and central WA continuing into next week," the bureau warned."Locations likely to be impacted include Kununurra, Marble Bar, Newman and Wyndham."
A total fire ban is in place for many areas of the state, with temperatures in the high 30Cs.
A blaze in Parkerville, in Perth, that started when a tree fell onto powerlines razed three homes. (Aaron Bunch/AAP PHOTOS)
Residents in Lancelin, 126km north of Perth, were forced to flee to the fishing town's jetty late Wednesday as a blaze that started on a golf course bore down on them.
29°C