Players at the Australian Open have been forced to put down their racquets and hundreds of spectators have been treated for heat exhaustion as extreme temperatures hit the country's south.
The heat has ignited bushfires which are threatening communities in Victoria and South Australia where temperatures climbed toward the mid 40s on Thursday, with more of the same due on Friday.
While Adelaide fell short of its all time record of 46.1C, it reached 44.2C to be the hottest city on earth, just ahead of Melbourne which hit a high of 43.9C, its hottest day since 46.4C on Black Saturday in 2009.
Roseworthy, just north of Adelaide, was the hottest place in the country with 46.4C.
And a Climate Council report says hotter days and longer heatwaves will occur in Australia more frequently
Co-author of the Australian Heatwaves report, Dr Sarah Perkins, said it is clear heatwaves are becoming more savage and are lasting longer.
"This summer and last summer have been characterised by extreme temperatures a lot of which have been record breaking," she said.
With temperatures in the mid-40s, Australian Open organisers invoked the extreme-heat policy and suspended matches on the outside courts.
Tennis fans also suffered with more than 970 spectators treated for heat exhaustion during the tournament.
The heat also strained the state's electricity network with the government warning that forced blackouts were possible.
Premier Denis Napthine said negotiations were underway with the state's biggest users to reduce consumption.
"We are running very close to capacity, our generators are all working flat out," he told reporters on Thursday.
The heat also added to firefighters woes, as they battled some of the worst conditions the state has experienced in five years.
Visitors to the state's Grampians National Park were told to leave the popular spot as two out-of-control bushfires merged to create a 1300-hectare blaze.
Fire Services Commissioner Craig Lapsley said 39 fires were classed as "going" on Thursday afternoon, after more than 1000 new incidents were reported in the past 24 hours.
Mr Lapsley said the volatile conditions were likely to continue on Friday.
Adelaide will endure its fifth successive day over 40C on Friday, with a forecast maximum of 42C before a cool change sweeps in dropping the temperature to 28C on Saturday.
The Country Fire Service is battling a string of fires on the west coast, Eyre Peninsula, in the mid-north, the southeast and the Riverland.
And with the triple threat of extremely high temperatures, rising winds and thunderstorms, the CFS says the emergency may get worse.
So far more than 150 people have been taken to hospital in South Australia with heat-related conditions.
Most of NSW escaped the worst of the heat, although Hay in the south reached 44.5C, while Canberra hit 40C.
Further south in Tasmania, Hobart experienced a reprieve from the heat with temperatures in the early 20s.
But with hot, windy and dry conditions predicted to return on Friday, a total fireban has been put in place for the entire state.
Hobart is predicted to reach 38C and Launceston 36C on Friday, while the central Highlands town of Ouse is expected to hit 40C.