SYDNEY: Australians sweltering through an extreme heatwave were warned that the worst was yet to come Thursday, with hundreds of fires raging in several states and temperatures nearing record highs.

Most of southeast Australia has been in the grips of a scorching heatwave that triggered a devastating wildfire on the west coast, razing 55 homes and claiming one life on Sunday.

The mercury has soared above 40 degrees Celsius (104 Fahrenheit) for successive days now in South Australia and there is a total ban on recreational fires in neighbouring Victoria where players at the Australian Open fainted, vomited and cramped up in blistering conditions.

Play was halted on Thursday afternoon due to the extreme heat, and a Melbourne school gardener, aged 76, died after collapsing on Wednesday in the grounds.

Health officials in South Australia said 129 people had presented to hospital in the past three days with heat exhaustion and dehydration. In Victoria there were 109 cases and ambulance services reported almost double the average number of call-outs for heart attacks.

Wildfires raged across both states, with South Australia´s Country Fire Service saying there were some 800 blazes of concern and an "escalating fire pattern over the next 48 hours", with total fire bans across the state from Friday.

"We may be reaching quite a dangerous phase in this heat wave and it´s important that people are well aware of those risks," said state premier Jay Weatherill.

"Because we appear to be getting closer to some of the cooler weather does not mean that the threat is receding. If anything the threat is increasing."

Acting chief meteorologist for South Australia, John Nairn, said the state capital Adelaide was on track to eclipse its hottest ever temperature of 46.1 Celsius, recorded in January 1939.

"We´re seeing today as a day where we may well set a record. We have a clear-sky day, the potential is there to reach that 46 degrees in Adelaide," he said.

In Victoria, 1,000 fires had been reported in the past 24 hours and 35 had taken hold. Friday is expected to bring horrific conditions for fire crews, with strong gusts and a wind change forecast.

"It´s the worst scenario possible but it´s a reality," said fire commissioner Craig Lapsley.

"It´s forecast for tomorrow."

Officials are warning of some of the worst fire weather in the state since 2009, when the so-called Black Saturday inferno killed 173 people and razed entire towns.

"To have four or five days of excessive temperatures during the day and during the nights is baking Victoria. It is taking the last amount of moisture out of any of the fuels," Lapsley said.

SOURCE: AFP