UPDATE: 11.30 am

At least 12 properties have been destroyed and two firefighters have been seriously burned as authorities battled blazes around New South Wales on Sunday.

A southerly change in the evening cooled temperatures and saw five emergency warnings downgraded to watch and act status after a day of extreme heat and more than 100 fires around the state.

The NSW Rural Fire Service (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 before later being downgraded to a watch and act after a southerly change impacted the fireground, with the fire moving north towards Leadville and Coolah.

Another fire at Beechwood, 50 kilometres 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.

A firefighter was injured after suffering burns at Boggabri, the RFS said. Initial reports of two serious injuries proved to be incorrect.

Firefighters are expected to get some relief Monday, with the Bureau of Meteorology (BoM) forecasting a cool change for much of the state.

“The good news is the next few days will see much milder temperatures across the bulk of New South Wales,” BOM senior forecaster Neil Fraser told ABC.

“We’ll see some high temperatures coming back to the west on Wednesday and Thursday.”

The NSW RFS issued emergency warnings for several blazes yesterday as soaring temperatures prompted authorities to describe conditions as “the worst ever” experienced in the state.

NSW RFS commissioner Shane Fitzsimmons said Sunday 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.

“At this stage we have got some unconfirmed reports of some homes being lost, sheds being lost, machinery being lost and other agricultural assets being lost on some of these fire grounds,” he said.

The fire at Dunedoo had been so big by Sunday evening it was creating its own weather system, Rural Fire Service deputy commissioner Rob Rogers told the ABC.

A man, 40, was charged after allegedly sparking a bushfire at Mangrove Creek, on the NSW Central Coast on Sunday. He was refused bail.

The arrest came just one day after police arrested a 13-year-old boy in Dubbo for allegedly starting a fire.

By early Monday morning more than 70 bushfires continued to burn across New South Wales, with one firefighter injured in a blaze near Boggabri in the state’s north–west.

That was an improvement from Sunday evening, when 2500 RFS firefighters were battling 97 fires across the state, with 37 of those not yet contained.

Almost 100 fires have been recorded since Saturday in NSW, with fire crews from QLD, ACT and Victoria waiting on standby.

The Sir Ivan fire, east of Dubbo, burned through 2000 hectares of bush on Saturday, before breaching containment lines on Sunday, and is said to be moving at 12km an hour in an easterly direction. It has reportedly burned some properties.

The Sir Ivan region Fire taken from a NSW RFS aircraft. Photo: AAP

The fire closed down the Golden Highway between Vinegaroy Road and Black Stump Way, and is expected to be closed until Monday, the RFS said in a statement.

Meanwhile, an emergency warning was issued for fires in Port Macquarie at Pappinbarra on NSW’s mid-north coast, Cumnock, Dondingalong, Beechwood.

Another blaze at Boggabri was downgraded from emergency to “watch and act” during the evening.

Residents were advised to seek shelter as it was too late to leave.

The RFS tweeted that a fire is also burning under catastrophic conditions towards houses in Kains Flat, north-east of Mudgee. Crews are currently undertaking property protection.

A statewide fire ban was in place for the entire weekend in NSW as temperatures swelled across the state’s north, with Scone and Walgett tipped to reach 46C and 47C respectively on Sunday.

The Bureau of Meteorology (BoM) said a trough was moving north-east from the central region earlier in the day, producing very hot, dry and gusty north-westerly winds.

“The forecast catastrophic fire weather conditions on Sunday in the upper Hunter and fringes of adjoining districts are rare in NSW. Sunday is shaping up to be the worst fire weather day so far of the season,” BoM acting NSW regional director Stephen Lellyett said.

Catastrophic fire danger ratings were in place for the Greater Hunter, Central Ranges and North Western, and an extreme fire danger forecast for North Coast, Northern Slopes, Upper Central West Plains and Lower Central West Plains.

The “watch and act” list was down from seven to two fires, which previously included Narromine, Myall River, Terreel, Wherrol Flat, Giro and Beechwood.

Police and RFS have blocked off the Golden Highway between Vinegaroy Road and Black stump Way #Leadville pic.twitter.com/bJsZN2bVdo

— Andrew Brown (@AndrewBrownAU) February 12, 2017

“With extreme fire conditions expected in this area today, fires could spread rapidly and may impact small remote villages and roads in the area,” RFS said.

Meanwhile in southern Queensland, the heatwave continues to intensify, with records tumbling in numerous towns.

Dalby broke Saturday’s February record with temperatures at 42C just after midday, the BoM tweeted.

In the state’s south, Toowoomba has broken Saturday’s all-time record, with the mercury at 40.8C.

Fire in #dunedoo today. Stay safe #nswrfs #rfs #nswfires pic.twitter.com/Qz7nZ8gXHq

— Lizzy Galloway (@LizzyGalloway) February 12, 2017

Deliberately lit

A 13-year-old boy, a 32-year-old man and a 40-year-old man were arrested in separate incidents for deliberately lighting fires.

RFS commissioner Fitzsimmons said the act of arsony was a “heinous act”.

NSW snakes may seek heat relief in homes

NSW residents be on the lookout for snakes seeking refuge. Photo: Getty

NSW residents living close to the bush have been warned to be on the lookout for snakes in their homes as the reptiles seek refuge from the heat.

Central Coast snake catcher and venomous snake expert John Mostyn said on Sunday that, contrary to popular belief, snakes did not enjoy very hot temperatures.

“When it gets about 35C, they actually want to cool down,” Mr Mostyn told AAP.

“That’s when they come into people’s houses, where it’s cooler.

“Laundries, garages and places like that, and if there are ponds around homes the snakes will head to them.”

Mr Mostyn, whose company, John’s Reptile Awareness Displays, runs snake handling courses said there had been an increase since Friday in calls to recover snakes from homes in the Hunter Region and on the Central Coast.

Red-bellied black snakes, green tree snakes and swamp snakes were among the species most commonly encountered.

He urged anyone who found a snake inside their home to remain calm and leave the room as quickly as possible.

“Stuff a towel under the crack under the door – that way they can’t get out through the crack in the door – and call a licensed snake catcher to come and get it,” he said.

“Don’t try to catch or kill it yourself.”

– with AAP, ABC