As 100km/h winds picked up, the heatwave moved from north to south, leaving no part of the state untouched.

"The worst conditions you'd see in February or March, we have seen today", Emergency Services Minister Lisa Neville told reporters on Thursday.

"This shows us what the risks will be in summer around Victoria, so we still have a long way to go to be ready."

The state's highest bushfire warning - Code Red - was issued for central and northwestern parts of the state.

Although risk was lower for the southeastern region, Ms Neville backed the statewide total fire ban to minimise danger posed to houses and people.

"It was a matter of time until we had the heatwave coming down here, looking at the conditions above our borders," Bureau of Meteorology forecaster Kevin Parkyn said.

"In over 30 years working at the bureau, I don't recall a day like this."

Melbourne's overnight temperature of 26C shied away from being the hottest on record. The city's 40.9C matched the 1894 record for hottest November day.

Laverton was the hottest town in Victoria at 44.3 degrees, while the southwest of the state had less extreme heat.

The weather is forecast to cool off during the evening, leaving milder temperatures during the weekend before heating back up to the low 30s on Monday.

"It's been a one day wonder weather. Monday will be hot, but we expect severe to very high fire danger ratings," Mr Parkyn told reporters.

Coinciding with the third anniversary of the thunderstorm asthma event which claimed 10 lives in 2016, the pollen count was set as "extreme" on Thursday,

A thick haze of earth-red dust blanketed Mildura, with locals telling AAP it has become the norm when winds take hold, given the drought conditions.

The high speed winds prompted more than 1000 requests of assistance for the majority for trees down, Emergencies Victoria reported.

More than 80,000 customers were left without power in the western part of the state, with Geelong, Bendigo and Ballarat hardest hit, service provider Powercor said.

Crews responded to more than 22 fallen powerlines, and 130-plus separate faults across the state which were impacted by the extreme winds.

"Due to the number of faults, extreme weather conditions and the need to be able to restore power safely, restoration times may be longer than usual," a statement says.

Australian Associated Press