Emergency warnings have been issued for about 50 towns between Hamilton and Port Campbell, across an area of more than 160km.
Several townships have been asked to evacuate while others have been told it's too late to leave.
A number of homes have been lost in west Cobden, but the exact number remains unclear.
Emergency Management Commissioner Craig Lapsley says firefighters are doing an exceptional job on the ground and in the air.
But the fire are made potentially more dangerous by a wind change expected today.
"We're getting the upper hand but it's still a dynamic environment," Lapsley said this morning.
"Traditionally in Victoria, in that sort of country, we lose more ground after the wind change than before." Paramedics have assisted more than 20 people, some with breathing difficulties, but there are no reports of major injuries.
The fires are threatening dairy farms and cows across the affected area, and some machinery has been hit.
"We have had reports of impacts on houses and farming machinery," Lapsley said.
A bushfire is heading towards the town of Hawkesdale and some locals are taking shelter at a basketball stadium in nearby Warrnambool.
Relief centres have also been set up at Hamilton, Colac, Camperdown, Port Campbell and Cobden.
The Terang-Cobden Road fire is the largest at about 12,000ha in size.
Firefighters battling the fires through the night were unable to save a power substation at Terang.
The fires are being stoked by strengthening winds, which are gusting at 100km/h, and a wind change is expected to push the eastern flank of the Terang fire towards the western foothills of the Otway Ranges.
A number of roads have been closed, including the the Princes Highway between Camperdown and Panmure, and many homes are without power.
Total fire bans have been declared for the Central and South West districts following unseasonably warm overnight temperatures.
The damaging and dangerous gusts were expected to ease into the late afternoon and evening.
- AAP
