Fire authorities say high temperatures predicted over the next few days will test control lines around the two major fires burning in Victoria.
A total fire ban is in force today in the South West, North Central, Central and Wimmera districts.
The Aberfeldy fire continues to burn in the area from Donnelly Creek, south of Aberfeldy, to areas north and north-west of Heyfield.
It has already burned 74,000 hectares.
Fire Services Commission Craig Lapsley says there are good containment lines around the fire, but there are lots of unburnt areas within the fire.
"If it gets going at the wrong time it could put embers out and have fires start outside the original fire," he told ABC local radio.
"It could escape into north of Coongulla, north of Heyfield, on the eastern side of the Glenmaggie dam."
Mr Lapsley says the fire at Harrietville, around the ski resort of Mount Hotham, is the sleeping giant.
He says it has been difficult to get containment lines around the fire and crews who had rappelled into the area, were pulled out yesterday when conditions became too dangerous.
"I think it's fair to say that's the sleeping giant," he said.
"Fire did come to the village this time last week.
"We'll see that play out again we believe tonight. And there's certainly plenty of resources up there to deal with it."
He says the situation in central Victoria is critical.
"It's absolutely tinder dry," he said.
"Some people are saying it's as dry if not drier than the drought conditions, but we've got fuel."
Mr Lapsley says the plan is to hit any new fire hard and fast.
"We've doubled the way in which we run our aircraft," he said.
"We've ensured the CFA in particular, where it might have been 15 trucks going to calls we're now seeing 20 and 30 trucks in the initial call."
© ABC 2013
14:43 EDT Tropical Cyclone Kate has only caused minor damage on Cocos Islands after passing to the north of the tiny community, more than 2,000 kilometres off the Western Australian coast.