The weather bureau says Queenslanders need to brace for heatwave conditions today, with fire authorities saying it is the fire season's most dangerous day in three years.
The Queensland Fire and Rescue Service (QFRS) says severe to extreme fire conditions are predicted in three-quarters of the state from Charters Towers in the north, west to the Northern Territory and down to the New South Wales border.
There has been a dangerous combination of scorching temperatures and low humidity in recent days.
Weather bureau senior forecaster Michelle Berry says Brisbane is predicted to get hotter than Birdsville, in the state's far south-west.
It will hit 39 degrees Celsius in Brisbane today and nearby Ipswich will reach 41.
Ms Berry says there are fire weather warnings spanning most of the state.
"We still have very hot temperatures all the way through central districts and up towards the tropics in fact," she said.
"The only real area throughout the state that will have below average temperatures looks like it will be south-west out towards Birdsville.
"They've had a cooler south-westerly wind change move through, so Brisbane tomorrow in fact will be warmer than Birdsville."
Weather bureau spokesman Rick Threlfall says it will be 35 on the Gold Coast, the Sunshine Coast can expect 38, Toowoomba will reach about 35 degrees, and the Mount Isa region is facing a "scorcher".
"The hottest part of the state will be up in the north-west where we could get up around 43 degrees," he said.
"Through the interior you're looking at Longreach around about 40 degrees.
"Probably the most unusual temperatures and affecting the most people will be down in the south-east.
"Adding in those fire dangers, it is going to be a fairly severe day down here in the south-east."
Queensland's chief health officer Dr Jeannette Young is urging people to take care of themselves and monitor others during today's heat.
Dr Young says it will impact on people with chronic conditions such as heart disease and diabetes.
"We will see increased numbers of strokes and heart attacks," she said.
"It's really important that the elderly and those with chronic disease really try and look after themselves.
"Try and stay where it's cool - go to the library or a shopping centre during the middle of the day - definitely not outside at all."
The Queensland Ambulance Service (QAS) says extra crews have been rostered on to deal with the expected rush of heat-related illness.
QAS superintendent Sean Mutchmor warns heat stress can kill.
"We're just looking for people to be cautious of everything," he said.
"Certainly there is the potential for people to be overwhelmed by the heat and any heat-related illness is a very important thing.
"It's very potentially life-threatening, so we would encourage people to be cognisant of that fact and stay well hydrated and try to keep cool as much as possible."
He says children and elderly people have less of an ability to identify their temperature as well as regulate it.
"With that being said, even your workmates - if you're a 45-year-old man that's working outside you're just as likely to be affected by heat-related illness, so we should all look after each other," he said.
Brisbane doctor Andrew Jeremijenko says the state's emergency departments will be flooded today with people suffering from the heat.
"We will see deaths today - it is just what happens," he said.
"It may not be from heat directly - it may be that heat aggravates one of the existing medical conditions and causes a death.
"It is very tragic when it happens and that is why it is important to take the necessary precautions and take care of anyone that is elderly, sick or young babies.
"I am actually working today and I am expecting a lot of people to come, particularly the elderly, people with other medical conditions.
"We do see an increase in heat-related illnesses and we see actually people get sicker with other illnesses that are exacerbated by the heat."
The RSPCA has urged the public to act if they see an animal in distress during today's hot weather.
RSPCA spokesman Michael Beatty says do not assume the animal is being looked after.
"The first thing you need to do is get an animal cooled down as quickly as possible," he said.
"If there's air-conditioning nearby obviously take it in to the air-conditioning.
"If there isn't, somehow get a cold compress - a rag, handkerchief or whatever - dip it in cold water and actually put it on the animals."
The QAS says people travelling in remote areas need to ensure they have plenty of water on board in case they run into difficulty.
Western Queensland paramedic Glen Scanlon says simple precautions are the best way to beat the heat.
"The basic things - about being smart on how you do things, try to schedule things within the day so that you are not having to do hard manual labour in the heat of the day," he said.
"Ensuring that your fluid intake remains high and the simplest way is to ensure you're drinking enough water that you are continuing to go to the toilet."
Mr Scanlon says most locals are well versed in managing the heat, but tourists can get caught out.
He says staying hydrated and being sensible about working in the heat are the simplest ways to cope with the rising temperatures.
Mr Scanlon says travellers in remote regions need to ensure they have plenty of water and supplies in their car and tell people where they are going.
He says people need to ensure they are continually well hydrated, because dehydration can creep up quickly.
"There are not the tourist numbers in these western areas during these warmer months, so there isn't the volume of traffic on a lot of the roads," he said.
"If someone was unfortunate enough to have a breakdown or a mechanical failure, to ensure that they've got enough water to remain there with their vehicle for a significant period of time, depending on how isolated the areas are they are traversing."
Mr Scanlon says people need to be sensible if they are required to work outside.
"It is not uncommon I suppose to have road gangs, or other work gangs, that would come from other areas to here.
"That can cause some issues if they are not familiar with how draining the heat actually is and how it can catch up on you.
"But with our local graziers, they are usually very smart as to how they do their business."
Surf Life Saving Queensland (SLSQ) is urging beachgoers to swim between the flags today with the scorching temperatures expected to draw big crowds.
SLSQ state president Ralph Devlin says parents should keep a close eye on their children when they enter the surf.
He says it is also important to drink plenty of water and be sun smart.
"One of the things that we experience is people coming to the beach with not enough sun protection or a hat or some sort of shade that they can apply," he said.
"Yet they sit there for hours when their skin's not accustomed to the sun, so being sun-safe is really important."
Emergency authorities will be on high alert today as large parts of Queensland face an extreme fire threat.
QFRS spokesman Peter Varley says today is expected to be the fire season's most dangerous day so far.
"Not only the high temperatures, but the lack of humidity and the trough moving across Queensland bringing behind it some very dry winds," he said.
"Under these conditions if we get a fire started [it would] certainly be very, very difficult to control and it will stretch our resources."
He says a battle plan has been drawn up.
"We have relocated teams to certain areas of the state and we have aircraft on stand-by etc, so we are prepared for anything that's going to happen."
Mr Varley says it is not too late for residents to act.
"They can still prepare their properties, have a plan for what they're going to do if fire does threaten them," he said.
Most fire permits have been suspended across the state.
Strike teams have been sent to Toowooomba, Warwick, Dalby and Roma and six water bombers and two fire spotters have also been deployed.
Firefighters in north Queensland have already been busy dealing with a number of blazes in the Townsville region.
Crews have spent the night battling six blazes near Bowen.
Other crews have been called to an 80-metre firefront near at Railway Estate in Townsville this morning and are preparing for further outbreaks.
Grassfires are being monitored on the Atherton Tablelands and near Mount Garnet in the far north, as well as near Mount Isa in the north-west.
© ABC 2012
15:56 EDT Residents in Western Sydney are sweltering in temperatures above 40 degrees as firefighters fight bushfires across New South Wales.