Fire authorities are investigating the cause of a blaze in a national park to the north of Dubbo on Sunday.
Flames burnt across about 2.5 hectares of the Goonoo Forest but an all-out effort by volunteers brought the fire under control.
On Monday NSW Rural Fire Service (RFS) Orana team manager Superintendent Lyndon Wieland confirmed the bushfire was being investigated.
"The fire started on both sides of the fire trail in about 60 metres, very suspicious and we're investigating it at the moment," he said.
Firefighters from five brigades responded to the Sunday morning call-out.
The Orana team manager praised their efforts, saying without their efforts "we'd be in all sorts of trouble".
"A fantastic job by the volunteers," Superintendent Wieland said.
"They really worked hard and for a long period of time to contain the fire.
"So at this stage, we'd still have a big fire on our hands again, other than the hard work the volunteers did for us yesterday."
The superintendent said the Nationals Parks and Wildlife Service were on the fire ground on Monday, "blacking out".
"We've still got heavy plant out there pushing some trees over that will cause us a problem later on in the day as things dry out, but it's contained at the moment," he said.
"...even little things like pulling up on the side of the road and talking on your mobile phone - your exhaust underneath the car could be touching on some dry grass," Superintendent Wieland said.
"All of those little things we need to be careful about.
"There's low fuel in the grassed area, but it doesn't take much for a fire to be really running.
"So we need to be very careful, very vigilant."
Mr Wieland said the region was getting a lot of smoke coming from fires in other areas, but if people saw a column of smoke or fire they should call triple zero.
"We will have a lot of smoke in the area from fires in the other area, if you see a column of smoke, it's a whole different ball game," he said.