Firefighters will continue to patrol the area and 'mop up', as NSWRFS spokesperson Greg Allan said, to ensure there are no hotspots around the impacted area, which is about 20 kilometres south of Wyangala Dam.

"That fire is contained, which is good news," Mr Allan said.

"We'll continue to have firefighters on the ground patrolling the area to mop up and put out any hotspots, if there are any. But there are no threats to property and this one is under control."

Crews first responded to reports of the fire at around 1pm on Monday morning and worked through the night to slow down the blaze, which was initially thought to have impacted about 180 hectares.

With the assistance of heavy plant machinery and waterbombing aircraft some 40-odd firefighters were on site at one point that night and into Tuesday, building and maintaining containment lines.

They were assisted by more favourable conditions on Australia Day, with some rainfall in the area also providing respite from the blaze, the size of which was reduced to 140 hectares as more information became apparent.

Despite the tough terrain, which proved a battle consistently, crews were also able to conduct backburning operations on Tuesday which strengthen and solidified those containment lines, going a long way to controlling the fire.

Crews continued through Tuesday evening and were once again assisted by heavy plant machinery and air support on Wednesday, making enough headway to upgrade the incident's status that evening.

Mr Allan said those in the area of Reids Flat should monitor conditions, follow their bush fire survival plan and take advice from firefighters in the area.

There could still will be smoke visible in the area, please only report new fires to triple zero (000).

The Central Western Daily relies on your support to keep doing what we do. If you're not already a subscriber, please consider coming on board. For as little as $3 a week for full digital access, a subscription represents great value.