A house has been destroyed near Moyston in the foothills of the Grampians, and the fire is threatening nearby Maroona.
Emergency Management Commissioner Craig Lapsley said Victoria's extreme temperatures and an expected wind change will combine to make the fire danger extreme.
He warns that the area most at risk of the spike in conditions includes the corner from Warrnambool to Horsham and Bendigo to Geelong.
'These areas are dry and experiencing high winds and because of the changing forecast there is a spike in the conditions from mid-morning into the afternoon,' Mr Lapsley said on Saturday.
He said Victorians needed to be aware of what fires were doing in their area.
'Make sure, as part of your planning, you know what you will do if a fire starts in your area and you cannot leave.
'Victorians travelling or already on holidays this weekend must understand the fire risk for both their route and destination.'
Residents of Maroona, near Moyston in Victoria's west, have been told to go to a relief centre in Lake Bolac as the Moyston fire moves toward the town.
The fire destroyed one home, four sheds and an unknown number of livestock on Friday as it burnt through 4714 hectares.
Firefighters used 80 vehicles and 11 aircraft to battle the blaze on Friday.
Temperatures are heading above 40C degrees in many parts of the state and strong winds of 50 km/h are gusting to 90 km/h.
Extreme Fire Danger Ratings are in place in the Mallee, Wimmera, South West, Central and North Central areas.
There is a Total Fire Ban in place for the entire state.
周六，最高火灾警告将扩展到北部中心区，包括including Mildura, Swan Hill 和 Horsham地区。风速将高达40公里/小时，最高温度为43度。