Sweltering temperatures have tested emergency services, with out-of-control bushfires north of Melbourne currently threatening the towns of Kerrisdale, Benloch, Nulla Vale and Pastoria East.

Emergency Management Commissioner Craig Lapsley said 190 properties were at risk, with residents urged to leave. Fire destroyed a home in Cobaw, about 80 kilometres north of Melbourne.

Premier Daniel Andrews said it was "absolutely on us" to acknowledge the state was facing a "long, hot and dangerous" summer.

"To be very clear, you've got to get your fire plan and you've got to do it right now. There's no time to waste," he said. "This cannot be put off until December or January or February. We have got a much earlier fire season.

"It's going to be a very, very challenging three or four months."

But Mr Andrews came under attack from Federal Environment Minister Greg Hunt, who said the Premier needed to explain why a controlled burn that started a blaze near Lancefield in central Victoria had gone ahead despite forecasts for a heatwave.

"I'll be writing to the Premier asking if they will review Victoria's controlled burn practices to make sure it happens early season when it's cool," Mr Hunt told 3AW.

In response, Victoria's Environment Minister Lisa Neville said: "Our focus right now is on the affected community. As with all planned burn escapes there will be an investigation into what happened, carried out by experts."

Mr Lapsley says the Lancefield fire was set last Wednesday by the Department of Environment, Water, Land and Planning on public land.

It jumped containment lines in hot, blustery conditions on Saturday and on Tuesday, dry heat and strong winds caused it to rapidly burn out-of-control, forcing evacuations as it neared property.

An emergency warning was issued at 2pm, after the blaze jumped the Three Chain Road and raced towards Lancefield. The south-westerly wind change about 4pm pushed the fire in a north-easterly direction towards Benloch and Nulla Vale.

An afternoon wind change is believed to have saved the Lancefield home of Adam Watkins and partner Prue Mathiesen.

Their 100-acre rental property is surrounded by a section of the Cobaw State Forest which was ravaged by the fire on Tuesday.

At one point the blaze had taken hold of their veranda and was slowly crawling up nearby trees.

"The wind was going a million miles an hour," said Ms Mathiesen.

"You just thought 'where do I start?'"

Mr Watkins said he was about to flee the area – having packed up the dogs and doused them in water – before the wind mercifully changed direction.

Two choppers also hammered away at the fire and a crew from the Carlsruhe CFA arrived to help.

"It was very very bad," said Mr Watkins.

"The fire was coming across the house. The only thing that saved it was the wind direction."

At around 8pm, small fires were still licking at the property. Ms Mathiesen said they would be sleeping in shifts as the night wore on, keeping an anxious eye for spot fires.

Mr Lapsley said the early start to the bushfire season would test emergency services but assured Victorians that fire authorities were prepared. Two NSW Rural Fire Service aircraft will be brought in to join 21 aircraft being used to fight fires throughout Victoria. A Hercules firefighting air tanker dropped fire retardant on the Lancefield bushfire on Tuesday evening.

With no rain forecast, Mr Lapsley said October weather would cause the state to dry-out, fuelling the potential for more bushfires.

He said the conditions were being fuelled by the weather cycle El Nino, and compared the state's condition to those back in 1997, when significant fires burnt land and property in the Dandenong Ranges and the on Mornington Peninsula.

Bureau of Meteorology duty forecaster Stuart Coombs said part of the state's west had only received about 50 per cent of its expected rainfall for the past two years, which had left trees and other vegetation dry.

"To have that drop for two years is very significant, particularly in forests. Trees get stressed and don't carry much water so they'll burn quickly," he said.

Mr Coombs said El Nino, which usually lasts about 12 months, was unfolding strongly in the Pacific and was unfavourable for producing rain across the country.

Melburnians sweated through a top temperature of 35 degrees on Tuesday, before a cool change brought much-needed relief at about 3.45pm. The forecast for Wednesday is 17 degrees.

with Allison Worrall and Richard Willingham