Key Points:

Weather watchers warn Australians will have to get used to more heatwaves after the record-setting temperatures that have scorched the country's southeast so far this year.

While Tasmania experienced its highest temperature on record, much of Victoria and South Australia baked in temperatures well above 40C - the highest being 48.2C at Kyancutta, SA, on January 28.

Victoria peaked at 45.8C at Avalon Airport on January 29, then Charlton on January 31, falling short of the state's record of 47.2C, while Adelaide also sweated through its warmest night on record, the mercury slipping to only 33.9C in the early hours of January 29.

Around the same time, RAAF Edinburgh, in the city's north, recorded 41.7C at 3.04am, fanned by strong winds. The Bureau of Meteorology said such an event appeared to be "without precedent" in the region.

Climatologist David Jones said global warming, while a key issue, was not the sole reason for the heatwave.

"It's a complex discussion ... global warming ... it increases the frequency of hot events and decreases the frequency or likelihood of a cold event.

"It's about relative probability. Look back over the last decade in Australia, we've had one or two really cold spells but we've had many more really hot spells and that's what it's about.

"It's not saying this heatwave has been caused by global warming, it hasn't - we've had heatwaves in the past," Jones said.

"But the likelihood of this has been increased by global warming, the severity of these events has probably been increased by global warming and the likelihood of seeing these in future will increase further as the globe warms."

Jones, acting head of the National Climate Centre, said Australia was expected to experience warming of between 2C and 4C this century.

"We're going to be routinely seeing 45-degree temperatures in Australia come the end of this century under global warming," he said.

"We're seeing large increases in heatwaves globally over the last 100 years. That's going to continue, it's going to accelerate and really ... people are going to have to get used to these sorts of heatwaves, they're going to become a lot more frequent."

Meanwhile, flood-bound north Queensland is braced for another cyclone, but Deputy Premier Paul Lucas reckons the region's so wringing-wet already it can't take any more.

"It's like pouring water over a wet towel," he said on a visit to the most sodden area around Ingham, between Townsville and Cairns yesterday.

"If we get another cyclone that dumps more water the ground can't take any more."

Ingham has copped 366mm rain over the past 24 hours, on top of more than 400mm dumped in the previous few days by ex-tropical cyclone Ellie.

Almost 3000 homes in the town have been affected by the flooding with 50 inundated and dozens of people evacuated to emergency accommodation at a local high school.

The town is waiting for river levels to drop from the peak of 12.25m to 7m before the clean-up can begin and experts can assess the damage, which is expected to exceed A$110 million ($142 million) across the region.

Severe weather warnings apply for much of north Queensland.

Mercury rising

Victoria and southern South Australia have this year recorded their highest temperatures since 1939:

* The highest was 48.2C at Kyancutta, SA, on January 28; Victoria's peak was 45.8C, first at Avalon Airport on January 29, then at Charlton on January 31.
* RAAF Edinburgh, north of Adelaide, recorded 41.7C at 3.04am on January 29, which the Bureau of Meteorology said was "exceptional".
* Melbourne had no measurable rain after January 3, the rainless period of 32 days the longest since 1956.
* Melbourne's record stretch of no rain is 40 days set in 1954-55.
* Tasmania had its highest temperature on record, 42.2C at Scamander on the island state's east coast on January 30.

- AAP