As south-east Queensland deals with hot weather, as well as smoke from the NSW bushfires, there is hope for rain in the region over Christmas.

Key points: People with breathing problems like asthma are being urged to stay indoors

People with breathing problems like asthma are being urged to stay indoors Rain is expected for Brisbane and much of the south-east region on Christmas Day

Rain is expected for Brisbane and much of the south-east region on Christmas Day Authorities expect to treat as many as 200 people over the next four weeks for heat-related illnesses

People with breathing problems like asthma are being urged to stay indoors, with the dangerous conditions set to linger for a few more days.

Bureau of Meteorology (BOM) forecaster Jess Gardener said she had not seen the smoke this bad before, with it also spreading as far as New Zealand.

"It is incredibly extensive — you can see the smoke on the satellite images certainly across the majority of Queensland and I think it's crossing most of Australia," she said.

The BOM said while temperatures on the coastal fringe were expected to moderate to the low-30s from tomorrow, further inland at Ipswich and Gatton they were expected to be in the mid-40s.

While welcome rain was expected for Brisbane and much of the south-east region on Christmas Day, outback towns like Birdsville were expected to swelter.

"It will be a pretty hot day, with temperatures around four to eight degrees above average, so out west we're looking at temperatures around the mid 40s," Ms Gardener said.

Smoke haze shrouds homes below the Mount Gravatt lookout. ( ABC News: Curtis Rodda )

Ian Simpson, owner of the Western Star Hotel Motel in the western Queensland town of Windorah, said the town was used to dealing with 48 degrees Celsius heat.

"Outside you really feel a bit of humidity, but hopefully that's bringing something [rain] with a bit of luck," he said.

He said the current high temperatures were "pretty normal".

"You tend to stay inside as much as you can, or a lot of people go down to the beach at the creek and set up camp down there with some gazebos and that — try and keep as cool as you can," he said.

Ian Simpson, owner of Western Star Hotel Motel in Windorah, says the town is used to dealing with 48C heat. ( ABC News: Maddelin McCosker )

Hope for rain over Christmas

Weary farmers in the drought-stricken Granite Belt region would no doubt be celebrating if predicted showers and thunderstorms eventuated.

"It could bring rainfalls to the whole south-east," Ms Gardener said.

"We're hoping there should be some useful rainfall totals in it, which is obviously really helpful for anywhere where we're seeing these fires continuing, and where we've had drought-declared areas for some time."

Severe fire danger warnings remain in place for the Central Highlands and Coalfields, and the Northern Goldfields and upper Flinders districts.

"They have severe fire dangers through today, much of the rest of the state has high to very high fire dangers," Ms Gardener said.

"We will see those fire dangers ease back to high very high across the whole of the state from tomorrow and that will continue for the next few days."

Beware heat-related illnesses

Dr Faye Jordan, an emergency specialist from the Prince Charles Hospital in Brisbane, said authorities expected to treat as many as 200 Queenslanders over the next four weeks, and as many again in February, for heat-related illnesses.

"There are some things that people can do to mitigate that, but I think that the general population are not particularly aware of the impact of heat on our health," Dr Jordan said.

"There is a real danger period for becoming seriously dehydrated, which makes people highly vulnerable to a high range of conditions, some of which can turn potentially deadly in a very short space of time.

"So this time of year we're not in our air-conditioned comfortable offices, we're not necessarily sitting around doing sedentary things either, but we're outside and we're in the hot environment — we're engaging in exercise and activities."

She said some people were probably drinking an excess of alcohol at this time of year.

"That's not a way to stay hydrated — what we need to do is we need to make sure that we stay in the shade, that we keep cool, that we drink water," she said.

Dr Jordan said the elderly living alone, and children, were most at risk.

She said the warning signs included headaches, confusion and reduced level of consciousness at the extreme end.

"I guess one of the easy things to look at is whether you're still going to the bathroom, whether you're still peeing, because if you're not then your body is saving all of your water and you need to remember to hydrate," she said.

A view of the smoke blanketing Brisbane on Sunday morning. ( ABC News: Anna Hartley )

Rain would be 'the best Christmas present ever'

Fabian Johansson and Kristoffer Gregenas have travelled from the cold temperatures of Sweden to the "hot and humid" weather of the Gold Coast.

"I saw a lot of articles like Australia is hitting record heat and so we're preparing for a lot of hot weather," Mr Johansson said.

Mr Gregenas said "if it's 25 [degrees Celsius] we're still happy, because we're used to it being so cold".

As for the expected Christmas Day rainfall, Mr Johansson said it was "a great Christmas gift for Australian people".

Swedish tourists Fabian Johansson and Kristoffer Gregenas are holidaying on the Gold Coast. ( ABC News: Dominic Cansdale )

Julie Dahl, a cattle farmer from Miriam Vale, said she had been cooling off in the Gold Coast sea breeze during her time off.

"The clouds are looking great — we just hope it's the same in Miriam Vale," she said.

She said the prospect of rain would be "the best Christmas present ever" but would "have to be for a couple of weeks to make a difference".

"We're feeding cattle at our property in Miriam Vale at the moment and that would be best thing that we need."