On Monday, each state and territory will produce a "heat wave" with meteorologists who say that rising temperatures will last for days in some parts.
The Bureau of Meteorology said warm days are expected in January but more days in a row of temperatures above 40C were unusual.
"Particularly north of southern Australia, they are looking at maybe five days in a row above 45 and could normally only have five or ten in the year," meteorologist Dean Narramore said on Sunday.
Low-intensity heatwaves were predicted in all parts of central Western Australia to the southern parts of the Northern Territory, in southwestern Queensland and through New South Wales, Victoria, Tasmania and South Australia.
Some regions will not be affected There are more severe and extreme heat conditions in each state, moving east and north-east of the NSW and southern Queensland by the middle of the end of the week.
It comes from the back of the heatwaves during the Christmas and New Year period, with the hardest hit indoor areas.
Vacationers and those returning to work in Melbourne can expect to see some days between the years ½ and a half, while a sea breeze will protect Sydney
But that relief will not extend to the western suburbs of the city , where Narramore said that residents in Penrith and Richmond would be suffocating for four or five days above 40 ° C.
A tropical bass could lurk off the west coast of Australia, creating stormy weather on Sundays and Mondays, but then he will move off the coast, he added. "It could become a cyclone but it will not come anywhere near the coast."