Ten children were left in cars across Melbourne as temperatures soared into the high 30s in a heatwave sweeping the state.
Victoria will swelter for a few more days to come, and authorities are urging people to look after themselves and each other.
"We need to make sure we get into the habit of looking before we lock our car," Ambulance Victoria heat health commander Justin Dunlop told reporters about 3pm on Thursday.
"It's not okay to leave kids in cars. Sadly we've already sent ambulance crews to 10 cases today so far.
"We need to do better, lots of people are doing good work, but there's room for improvement."
A watch and act fire alert was also issued on Thursday afternoon for a blaze burning at Shoreham on the Mornington Peninsula.
State response controller Dan Stephens said there were 37 fire appliances, two air cranes and another heli-attack chopper fighting the fire.
He said while the fire was in proximity to homes and the alerts remained in place, fire crews were so far keeping it away from properties.
The heat started in the west of the state, with Warrnambool becoming the hottest town early, reaching 34C by 10.30am and climbing to 39.7C at 1.50pm before a sea breeze brought a cool change.
Temperatures also hit 39.9C at Avalon and 36.7C in the Latrobe Valley.
"We're in the grip of a heat wave across Victoria," Bureau of Meteorology senior forecaster Kevin Parkyn told reporters.
"These heatwave conditions are likely to persist into early March."
Mr Parkyn forecast the warm weather would continue until March 5, especially across northern Victoria.
Friday to Sunday will continue to be hot and dry, with a risk of dry lightning on Sunday.
A total fire ban has been declared for southwest Victoria for Friday.
Mr Stephens reminded people looking to rivers and oceans to cool down to swim at patrolled beaches and stay cautious at inland waterways, after 23 people drowned in Victorian waters this summer.
The Chief Health Officer has issued a heat health alert for the central district through to Saturday.
An alert has also been issued for the southwest district on Friday, and the north central district is approaching the threshold for its own warning.
"Extreme heat can affect anyone. Pregnant women, people with a pre-existing medical condition, people aged over 65 and children and babies are most at risk," the warning said.
Australian Associated Press