Five emergency-level blazes have torn through bushland, rural properties and the suburb of Parkerville in Perth's hilly east in the past two days.
Crews have faced "intense fire behaviour" driven by strong and gusty easterly winds and low humidity.
No emergency warnings were in place in WA early on Friday following threat downgrades but Fire and Emergency Services Commissioner Darren Klemm said the situation was unlikely to improve for days.
DFES Commissioner Darren Klemm says aircraft are helping to bring the Toodyay fire under control. (Richard Wainwright/AAP PHOTOS)
"We haven't got a great forecast, particularly the next three or four days," he told reporters from the Parkerville fire ground late on Thursday.
"Certainly from here through to Boxing Day we're going to have some really challenging conditions across ... the southern half of the state."
The Parkerville blaze, which started accidentally on Thursday when a tree fell onto powerlines, has destroyed two homes, but authorities warn there could be more.
The alert warning for the area was at watch and act level early on Friday but residents were warned there was still a possible threat to lives and homes as conditions may change.
Firefighters have been battling an intense blaze at Parkerville, Western Australia. (HANDOUT/DEPARTMENT OF FIRE AND EMERGENCY SERVICES WA)
Firefighters are also battling blazes in the Shire of Toodyay, 90km northeast of Perth, and the Shire of Dardanup, 180km south of the city.
The Toodyay fire in the Wheatbelt region started on Wednesday afternoon and has burned through about 155 hectares of vegetation.
"We have a significant amount of resources out there, as well as aircraft, helping to bring that breakout under control," Mr Klemm said.
A watch and act warning was in place early on Friday for parts of Eaton, Glen Iris, Pelican Point, Picton and Picton East in the Shire of Dardanup and City fo Bunbury.
Residents there have been told there is a possible threat to lives and homes as a fire is approaching.
Crews also continue to battle a blaze in parts of Callcup, Crowea and Meerup in the Shire of Manjimup in the state's southwest, which was also at watch and act level early on Friday.
Firefighters in WA have been battling a series of intense blazes. (HANDOUT/DEPARTMENT OF FIRE AND EMERGENCY SERVICES WA)
Light rain has started falling in the area but residents have been warned the blaze remains out of control and continues to pose a threat.
The fire has burned about 3000 hectares of vegetation and there have been reports of damage to sheds, fences and farm equipment.
"It is burning in some very dense old-growth forest and this fire could continue and we're expecting it to continue for the next several days." Mr Klemm said.
Mr Klemm will meet with fire commissioners in other states on Friday to discuss whether interstate teams will be needed to help battle the fires.
Another bushfire that threatened the fishing town of Lancelin, 126km north of Perth, late on Wednesday was declared contained and controlled early on Thursday morning.
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