
Heat-stricken koalas have been pictured drinking from the water bottles of concerned residents in Adelaide as the city hit a sweltering 42 degrees on Saturday.

People and wildlife alike have been battling to beat the heat as an extreme heatwave grips the southern states, with hundreds being admitted to hospital for heat related issues.

Melbourne hit 41 degrees on Saturday and the city was set to drop to 28 in the evening, which would make it the hottest December night the city has seen since records began.

A cool change is set to sweep across both South Australia and Victoria on Sunday, bringing temperatures down to the mid-20s - but not before another scorching morning which could see Melbourne climb to 36.

Crowds were seen flocking to beaches in droves in hopes of seeking respite from the soaring temperatures - but wildlife had to use some less conventional approaches to cooling off.

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A resident gives a drink to a wild heat-stressed koala in her backyard in Adelaide, where an extreme heat wave is gripping the city

People and wildlife alike have been battling to beat the heat as an extreme heatwave grips the southern states, with hundreds being admitted to hospital for heat related issues

Adelaide is experiencing an extreme heatwave, with temperatures reaching over 40 degrees for five consecutive days

The heat-stressed koala seems relieved to take a splash of water over his back, a brief respite from the sweltering temperatures

Other images from Ironbank in rural Adelaide show the heat-stressed koalas lethargically slumping in trees

Wildlife in the southern states were ill-equipped to deal with the record temperatures

The footage of the koala was captured at the base of a tree in Dernancourt, Adelaide, after local man Mark spotted them looking parched.

Another image shows a rooster from Adelaide frolicking in a sink where he reportedly fell asleep while trying to cool off.

The likes of Glenelg beach and Henley beach were teeming with people on Saturday as the city topped a sweltering 42 degrees.

Those who could find the energy can be seen flipping off the jetty at Henley beach or paddling around on boogyboards, but most were content to lay out a towel and soak up the rays.

A hospital services spokesman said in Victoria alone, about 200 people had health issues relating to the heatwave by mid-afternoon.

They included respiratory and cardiac issues as well as heat stroke.

He called for people to check on neighbours and family members to ensure their safety.

'We'er already stretched in terms of resources,' he said.

Wildlife with no access to the beach had to employ less conventional approaches to cooling off - such as this rooster who went to sleep in a sink

Adelaide residents sunbathe on Henley beach as the extreme heatwave rolls onacross the city

Beachgoers ride boogie boards on Henley Beach amid the soaring temperatures on Saturday

The blistering conditions have been blamed on a stationary high pressure system in the Tasman Sea which has been dragging hot air from the centre of Australia

A man plays in the water at Glenelg beach, Adelaide, during the heatwave on Saturday

Adelaide residents cool off by riding on a water slide at Glenelg beach, as the experiences its first ever run of four days above 40C in December since records began

Adelaide residents escape the heat by jumping from the jetty into the ocean at Glenelg beach on Saturday

Adelaide residents sunbathe on Glenelg beach during an extreme heatwave, with temperatures reaching over 40 degrees for five consecutive days

In SA, more than 100 people have been hospitalised with health issues relating to the heat in the past three days, a number expected to rise before the end of the heatwave.

The SA capital of Adelaide has been suffering through a heat wave for the past five days, which was forecast to peak on Saturday at 44C.

The city will have its first run of four days above 40C in December since records began if the temperature is reached.

The blistering conditions have been blamed on a stationary high pressure system in the Tasman Sea which has been dragging hot air from the centre of Australia.

The heatwave left an apprentice carpenter fighting for his life after he collapsed on a building site on Wednesday.

Travis Mellor, 17, was admitted to hospital in a critical condition and in a coma, but regained consciousness on Saturday, The Advertiser reported.

He had spoken a 'few words' to family but remained very weak, it was reported.

Despite some positive signs, there were also long-term health concerns, such as possible damage to his kidneys.

A little girl plays in a water fountain in Moseley Square in Gelenlg, Adelaide, in an attempt to keep cool on Saturday

Emergency services remain on high alert in Adelaide, with extra services on standby for heat-related ailments

Victorian paramedics have issued a grave warning to stay vigilant and hydrated ahead of a forecast for a record 41 degree heat on Saturday

Ambulance Victoria's director of emergency management Paul Holman urged people to stay vigilant and hydrated in the sweltering weather

The soaring temperatures are a taste of what's to come in Melbourne as the city prepares for a 41 degree forecast on Saturday

The severe heat has also forced Thoroughbred Racing SA to cancel a scheduled race meeting at Morphettville Racecourse in Adelaide on Saturday.

Wildlife and conservation parks on the Eyre Peninsula will also be closed.

In Victoria, strong wind gusts up to 80km/h on Saturday made firefighters' jobs difficult in dry conditions.

'The fuels are now absolutely dry in most parts of the state, and when we get dry fuels, it means where fire starts, they are more intense, more difficult to put out,' Emergency Management Commissioner Craig Lapsley told reporters on Friday.

Mr Lapsley said the winds and heat would continue to build throughout the day, with extreme fire danger ratings issued for large parts of the state.

'The most serious part of the weekend is certainly Saturday afternoon,' he said.

A total fire ban was declared for Victoria on Saturday and Sunday.

Melbourne hit 41 degrees with the city set to experience a record breaking 28 degree low in the evening,

A man takes a shower at Glenelg beach, Adelaide, on Saturday, as temperatures pushed past 40 degrees for five consecutive days

A home decor shop in Keilor, VIC, was offering shoppers free chilled water to help beat the heat on Saturday

Malcolm Turnbull has issued a warning for Australians to take precautions during the extreme heat engulfing the south-east of the continent

Friends escape the sweltering conditions with some ballgames in the water at Melbourne's St Kilda beach

The beach was awash with Melbournesiders on Friday, and the crowds are expected to spill onto the weekend as the soaring temperatures continue

A beachgoer paddles blissfully along as the temperatures continue to soar in Melbourne

Extra precautions have been issued for those with pets, who are in even greater danger in the extreme heat

The Bureau of Meteorology issued fire weather warnings for large swathes of SA and VIC, with extreme fire danger in some areas.

Prime Minister Malcolm Turnbull, thousands of kilometres away in Japan, was also warning Australians to take precautions during the extreme heat.

People in bushfire-prone areas should implement their fire plans and keep watch over elderly neighbours, Mr Turnbull urged from Tokyo where he is due to meet Japanese prime minister Shinzo Abe.

'Given the extreme heat ... and its likelihood of continuing over the next few days, it is absolutely imperative that everybody takes all precautions they can to protect lives and property,' he said.

Such a run of hot weather has not been recorded for December since European settlement, according to the BoM.

St Kilda beach is one of several spots across the city flooded with crowds as the temperature skyrockets citywide

Fitness enthusiasts decided to brave the heat by jogging and rollerblading along the beach

In Adelaide where thousands of people have been escaping the heat by taking to the beach

A beachgoer braves the baking rays by hopping on a paddleboard amid the week-long extreme heatwave

Scores of people in Adelaide have been treated for heat stroke as the city roasted in record December temperatures

The mercury climbed past 42 degrees in Adelaide on Friday and the Bureau of Meteorology predictions for Saturday were about 44 degrees