Australia Prime Minister Julia Gillard on Tuesday urged people living near the bush area to obey fire crews as temperatures soar across Australia.

Gillard said residents need to heed fire warnings since severe fire warnings have been issued in several states, with temperatures of more than 40 degrees Celsius expected in Victoria and South Australia.

"There are a lot of emergency workers who are on high alert today due to the extreme weather conditions in parts of Australia and the extreme heat," she told reporters in Canberra.

Australians have been asked to heed safety advice from authorities as much of the country swelters through what is already shaping up to be a record-breaking heatwave.

Temperatures reached 43 degrees Celsius in parts of Victoria on Monday when temperatures peaked between 4:00pm and 5:00pm (AEST).

Victoria's ambulance service treated 45 patients for heat- related illnesses on Monday, including four cases of children left in cars.

Earlier on Sunday, temperature reached 41.6 degrees in southern port city of Adelaide, gave the city its hottest start to a new year since the maximum temperature hit 43.1 degrees on New Year's day in 1900.

The oppressive conditions persisted Tuesday and the storms are not expected to bring relief from the heat when they arrive later in the afternoon.