The fast-spreading Duck Creek Pilliga Forest bushfire was burning about 17km south of the town of Narrabri - home to more than 12,000 people - and 21km west of Boggabri on Tuesday afternoon.
The fire was downgraded from emergency level to a watch and act about 1pm as crews had success controlling pockets of the fire when it entered farmland from the Pilliga.
"With easing conditions across the fire ground, firefighters are gaining the upper hand," the NSW Rural Fire Service said.
Smoke from the huge blaze was being carried as far as the Hunter and Sydney regions, affecting air quality ahead of a forecast southerly change.
Overnight, the Duck Creek Pilliga Forest Fire took a large 30km run to the south towards Rocky Glen and Stannix Park. Shelter Now messaging remains in place for several areas including Rocky Glen, Stannix Park, Baan Baa, Willala, Goolhi. More information: — NSW RFS (@NSWRFS) https://t.co/ceYIMDkWcw pic.twitter.com/2RYlCs2FHmDecember 18, 2023
Shane Allan's parents own Bohena Pet Motel on the Newell Highway, south of Narrabri, and he said the family was prepared to fight any fires that broke out on the property, which was fully booked for the holiday period.
"We're not going to be fighting the actual fire ... it's going to get to the tree line and then we're going to fight anything that gets past that," he told AAP.
"It'll burn all around us probably."
Mr Allan said two large fires were visible from the site, including one that appeared to be threatening from the north.
"This is a full-on bushfire, this one," he said.
"But we've had two and a half days of this. You stop panicking after a bit."
Overnight the blaze generated a thunderstorm from a pyro-cumulonimbus cloud system, which caused dangerous and erratic fire behaviour, according to the RFS.
Residents of Baan Baa, Willala, Goolhi, Rocky Glen and Stannix Park were told on Tuesday morning that their lives were at risk and it was too late to leave, before the warning was downgraded.
Narrabri Shire mayor Darrell Tiemens, who spent the night fighting the fire with other volunteers, said the blaze grew "very, very quickly".
"Luckily, I don't think we've had any homes lost yet - although we just don't know," he said.
Council staff and other workers had been doing 24-hour shifts to keep services online as the bushfire caused power outages along many local roads, Mr Tiemens said.
"Hopefully rain later this evening will bring a reprieve, it's just very unpredictable," he said.
The temperature hit 35C in Narrabri on Tuesday, however showers and a possible thunderstorm were expected in the afternoon and evening.
Evacuation centres have been set up at both Narrabri and Gunnedah.
RFS spokesman Greg Allan said the bushfire had been fanned by northerly winds overnight and during the morning, pushing the blaze to the south.
It was unsafe for building-assessment teams to access the fireground and work out if any properties had been damaged or destroyed, he said.
There were 63 fires burning across the state on Tuesday morning, including 15 that were yet to be contained.
No total fire bans applied, but a high fire danger rating was in place for an area stretching from Sydney west to the Victorian border.
Temperatures reached into the mid-30s for Sydney, parts of the mid-north coast, and northwest and central-west slopes and plains.
22°C