Temperature records are falling across Queensland as the state swelters through an extreme heatwave and braces for "horrendous" days to come.

Authorities have warned the next 48 hours will see an unprecedented combination of weather and fire conditions from Cooktown to Gladstone that could turn extremely dangerous.

Wind from a trough moving east over the state, combined with a hot and dry air mass will result in an unprecedented fire danger.

According to the Bureau of Meteorology, new all-time temperature records were set today in Cooktown, which reached 43.9C, while at Cairns Racecourse the mercury climbed to 43.6C.

Cairns yesterday broke its November heat record by an entire five degrees.

Queensland Fire and Emergency Services Commissioner Katarina Carroll said conditions tomorrow would be "horrendous".

"There is no rain in this and there is no respite,” she said. “I have exhausted troops out there as we speak."

In the coming days, a further 100 firefighters from New South Wales will join those who have already been deployed in Agnes Water. A further 225 have been requested from other states.

The sun peeks through the smoke haze near Bundaberg. (9NEWS)

There are fears a massive inferno north of Bundaberg, that has burned thousands of hectares of bushland since Saturday, could intensify again to become a firestorm - a destructive blaze that develops its own wind system.

An extreme fire danger warning is forecast for the Capricornia region, and a severe fire danger warning is in place for the Central Coast and Whitsundays, Central Highlands and Coalfields, Darling Downs and Granite Belt, Wide Bay and Burnett and Southeast Coast.

"There’s a wind change associated with this trough and any going fires that experience this wind change have the ability to broaden the fire front quite dramatically when the wind change hits it," Bureau of Meteorology state manager Bruce Gunn said.

“We see extreme fire dangers in Queensland maybe once every two years. We've seen it three times or more in four days.”

Fire analyst Inspector Andrew Sturgess said anybody in the vicinity of a fire needed to be aware of its ability to develop and change rapidly.

"These are conditions that we’ve never seen before, we'll see fire behaviour that we’ve never seen before," he said.

When the trough passes and the wind eases, heatwave conditions are likely to persist.

Premier Annastacia Palaszczuk this afternoon urged Queenslanders to "look after one another".

"We all need to help one another, and we need to make sure as Queenslanders we look after the next-door neighbour, the person down the road.

"These are going to be extreme heatwave conditions the likes of which we have never seen before."

She said on Sunday, Longreach and Mount Isa could see temperatures in excess of 45C.