The Bureau of Meteorology has forecast record-breaking heatwave conditions for four states over the coming days.
Southern Australia is set to experience temperatures some 10 to 14 degrees higher than usual for this time of year.
The extreme conditions developing will stretch from Western Australia's Pilbara district, and through South Australia into southern New South Wales and Victoria.
In northwest Victoria, residents could see maximum temperatures of above 40 degrees for four consecutive days for the first time in almost a century.
Ambulance Victoria's Justin Dunlop says people must look after their friends and family over the next few days.
Life Saving Victoria's Chief executive officer, Nigel Taylor, says car parks and beaches will be overcrowded over the coming days so people must plan their outings.
