Health authorities have urged people to brace for sweltering temperatures ahead of severe heatwave conditions in Australia’s south and south-east.

On Thursday, Kalgoorlie recorded its hottest February day in 80 years, with temperatures climbing to more than 45 degrees.

And on the first day of March, more weather records were smashed with Western Australia, South Australia, Victoria and Tasmania hit by the unseasonal heat.

“The conditions forecast for Friday and Saturday are equal to the worst we have seen this bushfire season,” Tasmania Fire Service chief officer Chris Arnol said in a statement.

“The community needs to be aware that we are still battling serious bushfires.”

Melbourne’s 38 degree temperature was the hottest start to autumn in three decades. Adelaide also sweltered, with temperatures of 40 degrees tipped.

The extreme heat prompted Victoria Health to issue health alerts for residents living in the state’s central and southwest regions.

Stay inside, keep hydrated and only travel in the cooler parts of the day are the key recommendations.

Despite the expectation of cooler conditions with the start of autumn, the weather bureau is forecasting a warmer season with less rainfall.

Victoria’s Bureau of Meteorology forecast tops of 36 degrees for Saturday and 33 degrees for Sunday.

Forecaster Dean Stewart said if the heatwave hit as predicted, it would be the hottest autumn start since 1989. In that year the city reached 38 degrees, 38 degrees and 33 degrees between March 1 and 3.

Victoria Ambulance’s Justin Dunlop encourages residents to remain cautious: “We need to keep hydrated, drink plenty of water and plan each day so we can maximise our travel when it’s cooler.”

#BOMOutlook for Autumn 2019:
🌧Rainfall likely to be below average for much of the north and east;
🌡Temperatures very likely to be above average across Australia. https://t.co/Q4oRtInSs0 pic.twitter.com/wzlXHQO5li

— Bureau of Meteorology, Australia (@BOM_au) February 28, 2019

At 5.30am on Friday, the temperature in Melbourne was 26 degrees and total fire bans were in place.

A severe weather risk is listed for the southwest region on Friday, while the rest of Victoria remains at a “very high” level.

Trouble sleeping? 😴 If you thought last night was stifling in #Melbourne, you'd be right. In fact, it was the hottest March night on record at Laverton (26.3C) and Melbourne Airport (25.4C). Two more hot nights to come 🥵 https://t.co/rMkaJWXckD #VicHeatWave #MelbWeather pic.twitter.com/zy6Abop44q

— Bureau of Meteorology, Victoria (@BOM_Vic) February 28, 2019

South Australia hit with fire bans across the state

Adelaide had its hottest week in almost a decade, with 40 degree temperatures tipped on Friday.

An extreme heatwave emergency warning was declared by the SA State Emergency Service for the entire state and seven districts were issued with a total fire ban.

Babies, young children, the elderly and pregnant women are said to be most at risk as authorities urged residents to stay indoors.

At least 15 people across the state were hospitalised over the past two days due to the extreme heat. Authorities warned those going trackside for the Adelaide 500 V8 Supercars to stay hydrated.

It’s a scorcher for @adelaide500 🏎🏁🔥 Make sure you’re always Holden on to a water bottle because you can’t a-Ford to get dehydrated. Don’t exhaust yourself. Seek shade, take it easy – you don’t want to be Nissan out on the fun because of heatstroke #heatwave #HealthyInTheHeat pic.twitter.com/f3W4GDxT7D

— SA Health (@SAHealth) February 27, 2019

Professor Paddy Phillips from SA Health said people need to take care of themselves during this extreme heatwave: “Keep the fluids up, that’s really important,” he said.

Melbourne and Adelaide are both forecast to drop to the mid-to-high 20s on Sunday.

Tasmania set to break heatwave records

Tasmania could break 11-year March records, as temperatures are forecast to soar into the high 30s and a fire ban is in place for three days across the south of the already fire-ravaged state.

Hobart is expected to reach 37 degrees on Saturday and may break its March record of 37.3 degrees from March 2008.

Some 55,0000 hectares of wilderness and bushland across the state was ravaged by scores of fires in Tasmania in January. Photo: AAP

Dry, hot and gusty conditions with the potential for thunderstorms increases the fire risk.

Tasmania Fire Service chief officer Mr Arnol urged people not to use fire even in areas not covered by fire bans.

Elsewhere around the country …

Brisbane can expect showers on Friday and relatively warm conditions, extending over the weekend.

Light rain is also forecast for Sydney and temperatures of around 27 degrees on Friday through to the beginning of next week.

Perth is expecting mild conditions ahead of warm weather early next week but The entire south-east of Western Australia has been issued with a total fire ban.

Thunderstorms are likely for Darwin on Friday and Saturday.

-with agencies