The 26-year-old was arrested shortly after the fire broke out in scrub near Boundary Street, just before noon.

It was the latest in a string of major fires in the Coalfields that emergency crews to battle in sweltering conditions, as temperatures threatened to reach the 40s.

The fire developed into an inferno that incinerated more than 30 hectares of bushland – not far from where another blaze ripped through the Coalfields scrub just before Christmas.

While Rural Fire Service Crews battled to control the fire and Fire and Rescue NSW teams protected properties, strong north westerly winds pushed the blaze towards Pelaw Main. 

Fire fighters got set up at the back of the old Pelaw Main colliery where they worked to bring the fire under control as it approached.

Jumbo water bombing plane DC-10 was sent from it’s hangar in Richmond to help water bombing helicopters inundate the fire from above, which was listed as “being controlled” at 4pm on Tuesday.

John Sams, a former fire fighter with a decade of experience, said the fire was "up there with the worst" he had seen. 

Mr Sams rushed to his friend's Boundary Street home after news of the fire broke, to help her protect the property. 

The home was within 15 metres where the fire reached the edge of bushland across the road.

"Flames were almost as tall as the trees,” Mr Sams said.

“We couldn't do much, just run back here with the hose. 

“We had some wood chips catch alight in the back from ember attack. The ember attacks are pretty bad.

"It was fast moving, high flames, it was right up there. 

“Thank god for the water bombers.

"These people lighting these fires, it's ridiculous. 

“Enough is enough, there’s too much life and property."

Tuesday’s fire at Boundary Street was the fourth major blaze in the Coalfields thought to have been deliberately lit in little more than a month.

Crews fought a major fire at Abermain and Neath in December, which burnt 1200 hectares of land, before a five hectare fire at Loxford caused a closure of the Hunter Expressway in early January.

Only last week, fire fighters were called on in sweltering conditions to extinguish a blaze in Kurri Kurri and Heddon Greta, not far from Tuesday’s fire. 

Remarkably, no lives or homes have been lost during the fires.