There will be little to no relief from the heat come nightfall with the mercury expected to remain about 26 degrees in the evenings. "We're going to have hot days and hot nights as well," Bureau of Meteorology forecaster Dean Narramore said. Heavily-armed police officers on patrol for the G20 Leaders' Summit will work regularly rotating shifts across the weekend in a bid to avoid heatstroke. Authorities have also advised protesters to carry plenty of water with them. "It's obviously going to be very oppressive conditions for our officers and for protesters. It's far from ideal, but we will just have to deal with the circumstances that that are being presented to us," Deputy Police Commissioner Ross Barnett said.

"We'd obviously like it to be a lot cooler than that, but it's not going to be." However, Mr Narramore urged southern Queenslanders to spare a thought for their counterparts west of the Dividing Range. "We'll get a couple of hot days, but unfortunately for our inland friends, they're going to stay hot all week and possibly into next weekend as well," Mr Narramore said. The central Queensland town of Winton is expected to be the hottest in the state next week, with 44 degree-temperatures forecast for Monday, Tuesday and Wednesday. In Longreach, the mercury is expected to hit 41 degrees on Saturday, 42 degrees on Sunday and 43 degrees on Monday, Tuesday and Wednesday.

Mr Narramore said a very hot air mass sitting over central Australia and a surface trough moving over the southern states were responsible for the looming heatwave. "The trough is pulling down these hot northwesterly winds, which will drag that heat towards southeast Queensland," he said. "That trough will move through southeast Queensland on Monday and Tuesday, giving us some cooler winds. But it's going to stall over central Queenslander allowing that heat to build up." A severe fire danger warning has been issued for much of the state. Rural Fire Service assistant commissioner Neil Gallant urged residents to be extra vigilant.

"This is some of the hottest weather and highest fire danger Queensland has experienced this season," Mr Gallant said. "Under these conditions, very hot temperatures combined with low humidity and increased winds create dangerous fire conditions where fires may develop quickly, spread rapidly and become more intense." He said firefighters and police would remain on the lookout for arsonists and negligent landowners. "People should never throw cigarette butts out of the car window and always be careful when operating machinery in grassed areas," he said. Mr Gallant said landowners who had conducted hazard reduction burns recently were also strongly encouraged to ensure their fire had been properly extinguished.

"Landowners who have conducted burns must make sure residual fires are contained so that they will not escape," he said. Further information on bushfire preparation can be found at www.ruralfire.qld.gov.au.