The weather bureau says hot temperatures over the weekend were just the start, with the mercury set to soar in Queensland.
Senior forecaster Brett Harrison says the towns of Roma, Charleville, Mount Isa, Winton and Longreach will see maximum temperatures ranging from 40 to 44 degrees Celsius today.
"Today we are expecting the hottest temperatures to be up through the north-western parts of the state around Mount Isa, down through the central and southern interior parts of Queensland and right through the Darling Downs and south-east coast and as far north as about the Bundaberg region," he said.
In Brisbane today, temperatures will rise to 33 and at Ipswich 36.
Mr Harrison says the south-east will really feel the heat tomorrow.
"Looking at 39 degrees as a forecast for Brisbane and Ipswich expecting up towards 41," he said.
Health authorities say it is important to stay in contact elderly family members and friends during the heatwave.
Weather records have been broken for November in parts of western Queensland.
There has been a run of 40-plus temperatures across the interior over the past 10 days from Birdsville in the far south-west, up to Longreach, Winton and Mount Isa.
While that is not unusual for summer, locals are reporting the heat has come early, with little rain.
Weather bureau spokesman Scott Adams says Mount Isa has broken a November record.
"Thirteen days over 40 [degrees Celsius] here and the previous record for November was 12," he said.
"One day last week was our second hottest November day."
The Queensland Fire and Rescue Service says conditions tomorrow are expected to deteriorate, with about two-thirds of the state facing serious or extreme fire threat.
Barcaldine Mayor Rob Chandler says graziers across the interior are now worrying about their feed supplies for livestock and the prospect of more lightning strikes igniting fires.
"The fact that we haven't had a lot of general rain or storms for that matter, the feed would be drying out pretty quick," he said.
"It's always a tough time of the year leading up to Christmas - it is always hit-and-miss storms in general and it is burning the feed off.
"With no rain in sight at this stage, except maybe an electrical storm that might light it up again, it is an awful time in the bush."
In central Queensland, temperatures are likely to reach 40 in the Central Highlands tomorrow, with 39 degrees in Rockhampton.
Meanwhile in north Queensland, forecasts from the Bureau of Meteorology suggest Wednesday will be the hottest day this week, with Mackay heading for 35 and Moranbah to hit 39.
Mackay weather bureau spokesman John McIllwham says those temperatures are well above average.
"Average for Moranbah 33.7, 34.9 - so four or five degrees above average with those north-east to north-west winds feeding into the Central Highlands and Coalfields," he said.
In the state's far north, there is no sign of the wet season, with daytime temperatures set to soar this week.
Cairns weather bureau spokesman Greg Connor says no rain is expected along the coast for the next three to four days.
He says while the drier conditions have kept temperatures below average at night, the hotter daytime conditions are set to continue.
"The maximum temperatures are about two or three degrees above average and by about Wednesday we think they could be anything between four and six degrees above average, so for the tropics at this time of year it certainly is a heatwave," he said.
© ABC 2012
18:19 EST The mercury is set to plummet tonight across parts of Tasmania, with some places possibly seeing their coldest night in around two years.