Two fire trucks and a white four wheel drive parked on yellow grass near trees as a helicopter flies through white smoke.

A fire has broken out near the Goulburn Valley Highway at Trawool in central Victoria. (Supplied: Yea Fire & Recue)

A bushfire is threatening properties south of Seymour in central Victoria as much of the state experiences hot and gusty conditions.

The fire is burning at Trawool, close to the Goulburn Valley Highway.

Emergency warnings were issued just after 1pm telling some residents of Kerrisdale and Trawool it was too late to leave as the fire burned in a south-westerly direction towards Flynns Road.

Others further south in Kerrisdale, Tallarook and Trawool, an agricultural district, were to urged to immediately leave, while a wider Watch and Act applied to those in Strath Creek down to King Parrot Creek Road, Tehans Road and Strath Creek Road.

The State Control Centre’s David Nugent said the fire was burning in steep terrain.

“It’s quite tricky country, a mix of sort of forested and sort of cleared area,” Mr Nugent told ABC Radio Melbourne at about 2:30pm.

“When the fire runs up those hills, it runs very quickly.”

He said there were some homes near the blaze and burning embers were being carried by strong winds, which are expected to turn south-westerly this evening.

Firefighters are now racing to build containment lines on the eastern and north-eastern side of the fire ahead of the wind change.

“We’ve got a few hours this afternoon that we’ll be trying really hard to make sure we stop the spread of this fire … so when the wind turns around it doesn’t create a big, long new front for us,” Mr Nugent said.

A helicopter with a water bucket hanging underneath it flies above green trees in front of white and brown smoke.

Authorities said the fire was generating burning embers that were being blown in the strong north-westerly winds. (ABC News)

Clive lives in Strath Creek and has told ABC Radio Melbourne he can see the fire from his property.

“A lot of it’s just smoke because of where it is … because it’s in the Tallarook, which is a forest, it’s not a great place for this fire to be burning,” he said.

“We all know things can change pretty quickly.”

Fire authorities on Monday warned Victorians that forecast heat, gusty winds and possible lightning strikes would create extreme fire conditions across much of the state today.

Temperatures are in the mid-30s in many areas, with winds reaching up to 40 kilometres per hour.

A cool change has slowly started moving in from the south-west, but it could bring severe thunderstorms and winds gusting to 90 kph in some parts.

Storms have already started generating lightning strikes in the south-west.

A photo taken of smoke rising from tree covered mountains with white wind turbines behind the smoke.

The fire has broken out in the Tallarook State Forest. (ABC News)

Emergency Management Commissioner Tim Wiebusch said the whole state remained a “tinderbox”, with high fuel loads remaining unburnt by last month’s bushfires.

Total fire bans have been declared in five of Victoria’s nine fire districts — the Wimmera, South West, North Central, Central, and West and South Gippsland.

Mr Wiebusch said authorities were concerned about all areas from Victoria’s west through to West and South Gippsland, including grasslands from Melbourne’s north-west suburbs through to the Geelong region.

The Bureau of Meteorology said the cool change was expected to reach Mildura, Ballarat, Geelong around 5pm and Melbourne between 6pm and 8pm, pushing through the north of the state and through Gippsland overnight.