Firefighters in Victoria and South Australia are battling to control dozens of blazes amid a scorching heatwave that has sent the mercury soaring.
Temperatures have been above 40 degrees Celsius to some areas, and relief is unlikely until the end of the week, the ABC reports.
In Victoria, dozens of fires are burning out of control on Wednesday, with an emergency warning issued for the Yaapeet fire in the state's Wimmera region.
The Country Fire Authority says more than 250 fires were started by lightning strikes overnight, and 15 are yet to be brought under control.
Several fires are also burning in South Australia, with conditions set to possibly worsen as temperatures again climb into the mid-40s.
Residents of south-east Australia are again sweltering, after Melbourne hit close to 43°C, while Adelaide experienced its fourth hottest day on Tuesday of 45.1°C.
Victoria's chief health officer, Dr Rosemary Lester, says the high temperatures are a serious health issue and paramedics say they are shocked by the number of children left locked in cars in heatwave conditions.
Ambulance Victoria's Paul Holman says on Tuesday there was a 40% increase in the number of cardiac arrests.
Trains ran slower with fears the heat could warp tracks and cause widespread delays. Thousands of people were left without power in Melbourne's inner-north after equipment failure sparked outages.
In normally cool Tasmania, AAP reports police had reports of melting bitumen as temperatures were about 18 degrees above the average across the state, hitting 40°C in Melton Mowbray and Bushy Park.
