Homes "exploded" as a massive grassfire that started on Melbourne's northern fringe burned through regional areas, residents say.
The 40,000-hectare fire that started near Mickleham on Sunday is believed to have claimed at least 10 houses and continued to threaten towns on Monday morning.
Kilmore resident Mark Schrimpton said the fire burned five homes along his road.
"You could just see houses exploding, it was absolutely incredible," he told ABC TV on Monday.
"It was just horrendous. You could see more smoke than flames at one stage."
Emergency warnings are in place for the areas of Kilmore, Kilmore East, Wallan and Darraweit Guim, Bylands, Chintin, Forbes, Springfield, Goldie, Goldie North, Tantaraboo and Willowmavin.
Watch and act warnings have been issued to Beveridge, Kalkallo, Mickleham and Clarkefield.
Incident controller Matt Gunning said it was unclear how many homes the fire had claimed so far.
"We've got some anecdotal reports of 10 houses lost but we expect that to increase in the light of day," he told ABC Radio.
Mr Gunning said the focus of the fire fight on Monday would be at Kilmore and the surrounding bushland.
"One of our risks today is if that fire happens to trickle out in a north-western direction," he said.
"There is some really rugged country and it will make control very difficult as we head back into warmer weather in the next few days."
Mr Schrimpton said the memories of the 2009 Black Saturday fires - during which 119 people were killed from a fire that started at Kilmore East - had taught residents to take precautions and leave as early as possible.
"A lot of people know that you've got to make your move early and I think a lot of people in Kilmore did," he said.
The CFA says the threats have eased from grassfire burning near Warrandyte, in Melbourne's outer east, and near Gisborne, north west of the city.
Three houses were lost at Warrandyte on Sunday, while the Gisborne blaze claimed a number of homes.
Advice messages remain in place for both fires, which have since been controlled.