Rural Fire Service crews across the North West Zone have been working around the clock since about 4pm on Saturday afternoon 18 February.

"A lightning storm came through and started fires at the top end of Walgett Shire and at the bottom end of Bogan Shire," said RFS District Manager David Nicholson this morning.

"Six fires started within the space of about fifteen minutes."

While a number of the fires have been brought under control, a fire near Girilambone continues to burn and additional brigades have arrived from Sydney to allow local crews to rest.

In particular, the Hermidale, Miandetta, Girilambone, Coolabah, Honeybugle, Nymagee, Geandale and Canbelego brigades have been working overtime.

"Two were in the far north, close to the Queensland border and they took a bit of a run to the east when they got into farmland," he said. "We got brigades onto it quite quickly and managed to contain it, although it did get into a bit of scrub so brigades are doing repeat patrols."

The fire in the Nangerybone State Forest near Bobadah, south of Nyngan, was also started by a lightning strike.

"Access there in the forest was very difficult," Mr Nicholson said. "We organised dozers and pushed our way in when the fire was a bit benign at about 9pm."

"The Bobadah fire has been contained now. There's some timber still burning but we're happy with it and just keeping watch."

Plenty of material to burn and tricky to access. PHOTO: Nyngan RFS HQ

The fire on Booramugga Road, west of Girilambone, around 50 kilometres north of Nyngan, has continued to keep multiple units occupied.

"That fire burned pretty hard in heavily timbered mallee scrub and it has continued to burn," said Mr Nicholson.

"We got containment lines around it but the thick vegetation and rocky and sandy terrain has been causing quite a bit of a headache. We've been hitting it with planes and helicopters."

Crews have been working around the clock around Nyngan. PHOTO: Nyngan RFS HQ

By Tuesday afternoon (21 February) the fire had burnt out more than 4300 hectares of scrub country.

To relieve the pressure, a 'strike force' of trucks and firefighters from Sydney arrived at around midday on Tuesday to assist local crews.

"The relief crews will do three 12 hour shifts through until Thursday 23 February," Mr Nicholson said.

"They'll backburn out from the containment lines so it doesn't pass through the lines, even with a bit of wind."

The strike force team from Sydney arrived at Nyngan RFS HQ earlier today. PHOTO: facebook.

"We have a bit of a window now to get containment done and really lock in those lines as there's no bad winds expected for at least a week."

The RFS do not expect the situation to remain stable for long with the region experiencing "typical summer storm weather."

"It's a summer cycle of really hot weather with a bit of moisture leading to storm activity in the early evenings," said Mr Nicholson. "Every afternoon we're getting lightning strikes in some part of our area and without accompanying rain fires will ignite."

"We had a small fire at Willow Downs, south east of Coonamble, last night but the brigade arrived quickly and it was extinguished."

Girilambone fire. PHOTO: Nyngan RFS HQ

The Girilambone fire was the only one still burning as of Tuesday lunchtime.

Mr Nicholson urges all residents and travellers to keep an eye our for smoke and to report fires promptly.