In a scenario that is becoming all too frequent for Australians, Southwestern parts of the Australian state of Victoria  and South Australia both face an extreme risk of bush and grassfires as temperatures surge as high as 40 degrees in a heatwave that creates extreme fire risk. Paramedics have treated more than 35 people who collapsed in the Melbourne heat today; 13 people were seriously affected.

The Country Fire Authority banned residents in four districts from lighting fires in the open air all day, and said conditions there are extreme or severe, the second- and third- highest levels on the danger scale.

The fire ban includes Melbourne, where it is expected to reach 40 degrees today and 37 tomorrow, before relief arrives with predicted thunderstorms and showers .

The weather bureau is expecting temperatures to stay in the high 30s in most Victorian towns and reach a peak of 43C in the state's southwestern district.South Australia’s Country Fire Service issued a severe fire danger warning for parts of the state as temperatures rise to the low 40s, and relative humidity falls to below 10 percent.

In South Australia, power has been cut to homes on the southern Fleurieu Peninsula and Hindmarsh Island to minimise the risk of bushfires.

Adelaide had it hottest New Year's Day in 112 years yesterday when the temperature reached 41.6 degrees, while Ceduna on SA's west coast recorded 46.2 degrees.