Properties were destroyed, a man was flown to Sydney with severe burns and a firefighter was seriously injured as authorities battled blazes around New South Wales on Sunday.
One small township in central New South Wales was all but destroyed by fire.
Residents in Uarbury said nine of the dozen or so homes in the town were burnt to the ground when the Sir Ivan fire near Dunedoo bore down on them yesterday.
A southerly change in the evening cooled temperatures and saw five emergency warnings downgraded to "watch and act", after a day of extreme heat and over 100 fires around the state.
The NSW Rural Fire Service (NSW RFS) downgraded the last blaze at Kains Flat about midnight.
At Leadville, near Dunedoo, a fire breached containment lines and was heading east toward Cassilis. It was downgraded to a "watch and act" at about 10pm AEDT after a southerly change has impacted the fireground, with the fire moving north towards Leadville and Coolah.
Another fire at Beechwood, 50km west of Port Macquarie was threatening properties, but was also downgraded to "watch and act" late on Sunday.
Other blazes at Boggabri and Dondingalong were downgraded from emergency to "watch and act".
The RFS tweeted at 5.20pm a person had been injured in a fire: "Boggabri: A member of the public is being flown to hospital in Sydney after suffering burns at this fire."
Later in the evening, the NSW RFS confirmed a firefighter had also sustained serious injuries.
The NSW RFS issued detailed warnings for all the fires with emergency warnings. People in some areas were instructed to leave, while others were told to seek shelter.
The 40,000ha fire had been burning since Saturday at Leadville near Dunedoo, east of Dubbo.
By Sunday evening 2500 RFS firefighters were battling 97 fires across the state, with 37 of those not yet contained.
Today has been the most dangerous day of fire conditions in NSW history. Catastrophic fire danger confirmed in several areas. #NSWRFS— NSW RFS (@NSWRFS) February 12, 2017
A 'difficult day' for NSW
NSW RFS commissioner Shane Fitzsimmons said it was a "difficult day" and he had reports at least one home had been lost in the Boggabri blaze and possibly several in the fire near Dunedoo.
A man, 40, was charged after allegedly sparking a bushfire at Mangrove Creek, on the Central Coast on Sunday. He was refused bail.
The arrest come just one day after police arrested a 13-year-old boy in Dubbo for allegedly starting a fire.
Mr Fitzsimmons addressed reports of arson throughout the state and said deliberately lighting fires was a "heinous act".
"How dare they, how dare you. It's a criminal act, it's a dangerous act," he said.
"You put the lives at risk of our firefighters, the vast majority of whom are out there doing it for free, simply to make a difference and protect their local community."
Temperatures ease, but threat not over
Temperatures across New South Wales and southern Queensland will drop today after three days of a record-breaking heatwave.
Several towns in New South Wales experienced new record temperatures yesterday.
The mercury in Walgett, near the Queensland border, reached 47.9°C while Taree and Port Macquarie also set new benchmarks with temperatures of over 46°.
The Bureau of Meterology Rob Taggert said conditions are expected to ease.
"We are certainly not going to see those widespread 45° over the inland parts at all, but having said that, we are looking at still fairly high temperatures, getting up to the mid-30s, although right along the coast we are looking at temperatures below 30°, so that's a lot of relief."
The Rural Fire Service said about 20 or so grass or bush fires are still uncontained and the threat is not over.
It said crews will be out today to assess property and stock losses.