TWO-THIRDS of Queensland is expected to be on bushfire watch as temperatures soar above 40C for the fourth consecutive day.
Authorities say the fire threat will intensify from the NSW border to the edge of the Northern Territory.
Temperatures in Brisbane are forecast to hit 39C tomorrow, making it the hottest December day in 11 years.
The heat has been even more intense in the state's west, with temperatures in Mt Isa and Longreach forecast to reach 43C today - the fourth successive day above 40C.
Controlled fires are presently burning at Beachmere, north of Brisbane and near Mount Isa, where a Brisbane-based fire crew was sent today.
Queensland Fire and Rescue director of rural operations Peter Varley said severe fire conditions were expected in two-thirds of Queensland tomorrow.
"Any fires that start will be extremely difficult to control," he told AAP.
"The farther west, the worse the conditions get."
Fire and Rescue Commissioner Lee Johnson says fire permits have already been suspended across Queensland.
"Residents who have obtained a permit to burn should defer any burning to a more suitable time as conditions are far too risky," he said in a statement.
The weather bureau's senior duty forecaster Michelle Berry said west to northwesterly winds of up to 50km/h in southeast Queensland would increase the threat of bushfire.
"We're looking at gusty winds, very dry conditions and very hot temperatures," Ms Berry told.
"This is the kind of temperature that is well and truly above average.
"We're looking at an increasing fire danger."
An enhanced fire danger for Brisbane is expected to continue on Wednesday, even as temperatures drop back to 32C.