Lightning strikes are blamed for two spot fires burning alongside the massive Grampians bushfire, which has claimed 24 homes and engulfed more than 125,000 hectares in Victoria's west.
More than 1,000 fire-fighters, and 14 aircraft, are battling the blaze but it continues to burn out of control despite intense efforts, according to the Country Fire Authority (CFA).
"Thunderstorms in the area have made weather conditions unpredictable as well as increasing the likelihood of new fires through lightning strikes," according to the CFA's website.
"Two lightning strikes have already resulted in fires at Mount Arapiles and Rockland Reservoir, which fire-fighters are currently attacking."
Eight rural communities, including the largely evacuated tourist town of Halls Gap, remain on high alert for falling embers.
The perimeter of the fire spans 350km, and the CFA reports along with 24 homes approximately 67 farms have lost stock including more than 60,000 sheep and 500 cattle.
Meanwhile, in Victoria's east, the Erica Moondarra fire is also entering an unpredictable phase, according to the CFA .
"Some rain activity is expected (today)," the website states. "If thunderstorms develop then erratic wind behaviour is also likely."
Fire-fighters should be assisted by lower temperatures across the state however the fire has already blacked out more than 14,500 hectares of bushland and continues to threaten eight communities.
"The fire remains active along its southern edge near pine plantations," the CFA said, adding more than 280 fire fighters, and nine aircraft, are attempting to bring it under control.
Meanwhile a fire at Kinglake, north of Melbourne, also remains active but fire fighters consolidated containment lines overnight.
"Patchy rain was experienced in the area last night by significant hotspots and fire activity remain," the CFA states.
It has claimed 1,200 hectares, and residents in Kinglake and nearby Castella remain on high alert for falling embers.
The Anakie-Brisbane Ranges fire, which had threatened homes in Melbourne's southwest, was on Friday listed as under control.
The fire has claimed 7,264 hectares.