Thousands of houses across Victoria are without power as the state swelters through an "oppressive" night of hot and humid weather.
About 5800 properties were without power on Thursday night, a spokesman for the State Control Centre said, with the cause of the outages under investigation.
The blackouts came after Energy Minister Lily D'Ambrosio urged households to ration their non-essential electricity use.
While "absolutely confident" there was enough energy supply to get through Melbourne's minimum overnight temperature of 29C - just shy of the 30.6C record - Ms D'Ambrosio suggested turning off dishwashers, kitchen appliances, washing machines and pool pumps.
"What we are asking Victorians to do is just be aware and be mindful that the activities we undertake when we're home do put that further pressure on our energy system," she told reporters on Thursday.
"Where you can, if you want to, put off doing that load of washing."
Australian Energy Market Operator CEO Audrey Zibelman said an extra 400 megawatts had been added to the grid.
"We are going forward and reactivating our reserve power (of) 400MW of additional energy."
"The system is being utilised to its maximum - what we need everyone to do is just be aware of that and over this peak period make sure that you are not wasting energy."
Victorians have been told to brace for an "oppressive" night following a top of 40.8C in Melbourne about 5:30pm.
The Bureau of Meteorology has revised its Melbourne forecast to 44C for Friday - the hottest maximum temperature since it hit 46.4C on Black Saturday in 2009.
"Northern Victoria (is) in record territory potentially with some forecast temperatures around 46C in places like Swan Hill, Shepparton, Mildura, the whole of northwest Victoria, in particular, is hot," the BoM's state manager Andrew Tupper said.
"Heat is a killer," Dr Tupper added, encouraging people to adapt their behaviour.
"It's going to be oppressive so it's not going to be a great morning to go for a run, during the night we need airflow," he said.
Authorities are urging people not to take risks during the hot weather, including leaving children in cars or swimming at unpatrolled beaches.
A cool change is expected late on Friday but it will bring gusts of up to 80km/h, thunderstorms and increased fire risk.
Fire crews are on stand-by while extra paramedics and ambulances are on call to assist those struggling in the heat.
Australian Associated Press