A string of Australian towns have become some of the hottest places on earth as a brutal heatwave pushes inland temperatures towards 50C.
Fierce heat has been gripping the nation's southeast for days, pushing forecast temperatures in the Victorian regional centre of Mildura to 49C on Tuesday.
The town of about 35,000 people is due to experience a series of 40C-plus days through to Saturday.
The outlook is much the same in the town of Ouyen, one hour south of Mildura, where temperatures are also forecast to peak at 49C.
The Mallee town, in the state's northwest, could set a new temperature record for the state.
It is a dubious honour for its 1100 residents, with Mildura mayor Ali Cupper describing the forecast conditions as "unheard of".
"If you're out in the heat, a couple of degrees can be the difference between life and death," she told AAP.
Emily Dalton, publican at Ouyen's Victoria Hotel, said the heat had been building steadily each day, with conditions becoming especially punishing by late afternoon.
The hotel has become a natural refuge as local businesses closed early and residents sought relief at the lake or the pub.
"Bring your dogs, bring your cats - the beer is cold and the food is good," Ms Dalton said.
The nearby town of Walpeup was first off the block, becoming the hottest town in the state at 12.30pm with a temperature of 46.2C.
While conditions are most extreme in the regions, the slow-moving heatwave has not spared the cities.
After sweltering through its hottest night on record, Adelaide got off to a scorching start on Tuesday, crossing 41C by 9.30am.
The temperature in the city reached 44.7C on Monday, topping its previous Australia Day heat record from 2006.
A cool change brought some reprieve to the capital shortly after midday and is set to deliver cooler conditions throughout the afternoon and evening.
Melbourne got off to a slower start but temperatures will continue to build, edging past 40C by mid-afternoon and forecast to reach a maximum of 45C in the early evening.
That would make it the city's second-hottest January day on record, behind the 46.4C day before the devastating Black Saturday bushfires of 2009.
Statewide fire bans are in place for Victoria and South Australia as multiple blazes burn out of control amid tinderbox conditions.
In Victoria, a fire in the Otways continues to burn after jumping containment lines on Saturday, threatening the small community of Gellibrand.
There have been unconfirmed reports of property losses within the fire ground.
The weather bureau has warned gusty southwesterly winds will reach Melbourne on Tuesday afternoon, with a risk of dry lightning from thunderstorms.
Deputy incident controller Alistair Drayton said the wind change was concerning, with residents in Gellibrand and surrounding areas urged to evacuate.
"The conditions mean the fire could spread quickly and unpredictably," he said.
"We strongly recommend people in affected areas enact their bushfire plan and leave early to protect themselves and their families."
Paramedics have also issued a warning after responding to 11 cases of children being locked in cars over the weekend as temperatures soared into the 40s in Victoria.
While Victoria and South Australia are set to be the worst affected, elevated temperatures are being felt nationwide.
Extreme heatwave warnings are in place across large parts of New South Wales, including the Snowy Mountains, southwest slopes and upper western regions.
In the outback town of Broken Hill, temperatures are expected to peak at a record 47C.
Severe heatwave warnings are also in place for parts of the Northern Territory, the ACT and Queensland.
