Devastated residents of a tiny northern NSW town have told how they feared they would die as a wall of fire closed in late on Tuesday.

One man told the ABC he messaged his mother to tell her he loved her as flames licked underneath the door of his Rappville house.

“I’ve got nothing. I’ve worked hard for a lot of my stuff, now it’s all gone,” he said.

“I’ve only got what’s on me, and my dog.

“It was crazy, it was intense, it was really bad.”

Up to 30 homes in the area, which is south of Casino and home to about 250 people, were destroyed or seriously damaged as several bushfires raged within about 100 kilometres of each other on Tuesday. Other residents suffered burns – and one has told how birds dropped out of the sky at the height of the inferno.

Other buildings, including the town hall, were also been lost.

“I’ve lost the bloody sheds, the house, lost everything,” Rappville resident Danny Smith said.

NSW Rural Fire Service superintendent Michael Brett said initial investigations indicate the Busbys Flat fire started on Friday night – and might have been deliberately lit.

“We have identified suspicious activity in that area,” he said.

“Our investigations are continuing.”

Police said on Wednesday afternoon there were still some people unaccounted for after the fire. The widespread nature of the fire in Rappville had made it difficult for authorities to access the fire ground and put a number on how many people were unaccounted for, acting police commissioner Dean Smith said.

NSW Emergency Services Minister David Elliott said anyone who’d put lives at risk would face the full force of the law.

“It really is a bastard act if you are going to put your own community at risk,” he said in Sydney.

NSW Premier Gladys Berejiklian said she was “horrified” to hear the fire was suspicious.

“I’m … shocked that anyone would think it’s smart to be lighting any of these fires – I hope that’s not the case,” she said.

RFS deputy commissioner Rob Rogers said the blaze wreaked havoc on Tuesday, ahead of what was likely to be a “very long summer” of bushfires.

Mr Rogers said on Wednesday that two fires – at Drake near Tenterfield and at Busbys Flat near Rappville – had united to form one large blaze that has already consumed 92,000 hectares.

Crews continue to battle the massive fire as they work to contain it over the coming days.

“We are still using that figure of up to 30 homes across these fires,” Mr Rogers told ABC TV.

“Unless we get some really meaningful rain, I think it’s going to be a very long summer.

“Before these fires, we had already lost around 44 homes in NSW due to fires so far this fire season, and obviously that number could climb significantly from these fires.”

#NSWRFS Building Impact Assessment teams will inspect areas impacted by yesterday's bush fires across northern NSW. At this stage, there appears to be a significant number of homes and other buildings destroyed. We're working to get residents back when safe to do so. #nswfires pic.twitter.com/zyQ2ULKVN6

— NSW RFS (@NSWRFS) October 8, 2019

More than 30 fires are still burning across NSW but the RFS hopes more favourable weather conditions will help them get the upper hand ahead of forecast weekend rain.

John Duncan, 83, was among those who lost his home in the Busbys Flat blaze – and is only alive thanks to social media, according to his daughter Carol.

Ms Duncan has set up a GoFundMe page to help her father, who she says “lost everything except the clothes he was wearing”. By Wednesday afternoon, the page had raised more than $14,000.

Ms Duncan said her father had moved to the area from Canberra after the devastating 2004 bushfires, “not wanting to go through it again”.

She said firefighters responded to a tweet asking for advice and went to his home to rescue him and his partner, Cass. They had taken shelter in a shed (“It’s steel, and steel doesn’t burn,” Mr Duncan said).

“The RFS people who went and got my dad and his partner OUT OF THE SHED thanks to Twitter … saved my Dad’s life,” an emotional Ms Duncan said on Wednesday.

What remains of my Dad’s home. #Rappville #NSWfires pic.twitter.com/gWxsb0ywdL

— Carol Duncan (@carolduncan) October 9, 2019

Cameraman Matt Coble said he watched in horror as the Busbys Flat fire came towards him over a hill.

He told ABC TV the wind was “cyclonic” and “unbelievable”.

“The roar of it, the speed of it, was unbelievable – I couldn’t imagine the speed of the actual wind.”

Mr Coble described the situation as “quite scary” and said birds dropped out of the sky in front of him.

The cause of the fire is being probed, with investigators working to establish whether it was accidental or started deliberately, the Deputy Commissioner said.

An evacuation centre has been set up at St Mary’s Catholic College in Casino for those who were forced to flee the Busbys Flat fire.

Meanwhile, fire crews have all but extinguished a “fast and furious” blaze that destroyed a house in south-east Queensland.

The flames that ripped through Laidley, in the Lockyer Valley west of Brisbane, on Tuesday afternoon are out, but burnt out logs are still smouldering.

This house at Laidley was destroyed by fire on Tuesday. Photo: AAP

The inferno flared up with little warning, catching firefighters by surprise as they were attending a fire at nearby Thornton.

The Laidley fire burned right up to the fence line in one subdivision.

One family’s home was destroyed, the fierce flames melting a boat and ute in the yard.

Lockyer Valley Mayor Tanya Milligan was monitoring other fires in the region when she got a phone call asking if she knew the fire was in her street.

She praised the efforts of emergency crews.

“We’re really blessed that we only had one loss of one home,” she said.

“It certainly could have been a lot worse.”

Twenty fires are still burning across Queensland, with cooler temperatures also easing conditions there.

Fire crews are still battling a blaze at Glen Rock in the Lockyer Valley. Some residents who were evacuated on Tuesday have not yet been able to return home.

No properties have been damaged there.

-with AAP