The threat from more than 100 fires burning across Australia's northeast eased over the past 24 hours, lawmakers and emergency workers said on Thursday, although unfavourable weather conditions are set to continue.

Emergency workers warned on Wednesday that a spate fires had reached emergency levels, triggering an evacuation of more than 8,000 people from the town of Gracemere, about 600 km (370 miles) north of the Queensland state capital, Brisbane.

Firefighters extinguished the biggest fires after working through the night.

More than 100 fires remained alight but none was considered to pose an imminent threat, the Queensland Rural Fire Service said.

Queensland Premier Annastacia Palaszczuk said residents must continue to monitor emergency warnings.

"What we experienced yesterday was off the charts," Palaszczuk told reporters in Brisbane. "We're still not out of the woods. There's still a long way to go."

The Bureau of Meteorology said temperatures across the state would ease to 33 degrees Celsius (91.4 Fahrenheit) on Thursday, down from the highs of around 40 C recorded earlier in the week.

Rain was also expected on Friday, the bureau said, offering some respite.

The hot, dry weather on Australia's northeast coast was in stark contrast to conditions in Sydney, Australia's largest city, on Wednesday.

More rain fell across Sydney on Wednesday than would normally be seen throughout the whole of November, the meteorology bureau said.

The torrential rain caused flash flooding, left hundreds of people without electricity and caused widespread transportation delays.