With temperatures set to soar through southern Australia, experts are warning elderly Australians along with those with pre-existing medical conditions are at greater risk of heat-related illness.
As Adelaide and Melbourne brace for five scorching days, Victoria's Department of Health has issued "heat health" alerts to warn about the dangers of extreme heat.
Chief health officer Dr Rosemary Lester said heat-related illness can be deadly and encouraged Australians to look out for those with pre-existing health conditions.
"The effects of heat-related illnesses can range from mild conditions such as a rash or cramps to very serious conditions such as heat stroke, which can be fatal," Dr Lester said.
"Importantly, heat may worsen the conditions of someone who already has a medical condition such as heart disease."
Monash University weather and climate associate professor Margaret Loughnan said elderly people and young children were also prone to heat stress, and should be checked on regularly.
Victorian Health Minister David Davis said during the heatwave leading up to the 2009 Black Saturday bushfires, 370 people died from heat-related illness.
Mr Davis said Ambulance Victoria had undertaken extensive preparations to cope with an expected increase in heat-related cases.
"They believe that they will have significant resources in place to manage what's coming," Mr Davis told reporters on Monday.
Temperatures will peak at 43C in Adelaide on Wednesday, while temperatures will hit 41 degrees in Melbourne on Tuesday and Thursday.