After breaking two temperature records in the last days, Australia is set to finish the week before Christmas facing temperatures well into the 40s across most of the nation on Friday.
Wednesday's average of 41.9C across the country was one degree hotter than the previous record set on Tuesday.
This average maximum temperature record could be broken again as the heatwave will only continue to intensify, leaving southern and central Australia with temperatures up to 16C above average by Friday.
Parts of Tasmania are also set to reach temperatures about 16C above the state average on Friday as the extreme heat gripping mainland Australia spreads south.
Melbourne is forecast to hit 44C on Friday. The last time it climbed that high in December was 1876.
The 39.3C that sweltered through Canberra on Thursday to set the capital's hottest December day might come a close second if the capital reaches the 41C forecast on Friday.
Adelaide could also be set for its hottest December day on Friday, with an upgraded forecast of 46C.
Australia continues to swelter through summer as the mercury rises. Sydney remains covered in smoke from nearby bushfires. Source: AAP
Brisbane and Darwin will begin a relatively milder weekend with maximums in the mid-30s.
Perth will hope to have a break from the bushfires with a partly cloudy forecast of 27C.
Sydney will have a break from intense heat and smoke with temperatures forecast to stay in the low 20s.
NSW premier Gladys Berejiklian declared a week-long state of emergency on Thursday morning, hours before dozens of homes were feared to have been lost.
