NSW Rural Fire Service ground crews tackled the fast-moving flames, which were being fuelled by severe winds with gusts up to 87km/h and high temperatures.

Riverina RFS operational officer Bradley Stewart said resources deployed included seven RFS trucks and "Bomber 277", a small plane, which departed Wagga airbase for one bombing run.

"We believe through reports from persons in the vicinity that it may have been a mechanical failing of a passing freight train, because the fire was within the rail corridor and the ignitions were indicative of a train which had passed through immediately before the fires were noticed," Mr Stewart said.

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"And local residents heard several large noises that they described as a bang or an explosion just prior to the fire being noticed."

Mr Stewart said fortunately the fires were hemmed in on both sides by the road and the rail corridor, which otherwise would have caused significant damage to rural properties in the Eunony, North Wagga and Bomen areas.

"The fuel loads, the weather humidity and the wind - had the fire become established we would have seen it spread well in excess of three kilometres an hour," he said.

The first fire broke out at Oura Road and Hale Street, on the eastern edge of North Wagga, about 3.15pm. It was listed as under control by 4.20pm, according to the RFS, thanks to a quick response.

A Fire and Rescue NSW spokeswoman said a second smaller fire, on Whittle Street, was quickly extinguished after burning through 50 square metres.

Wagga is one of the locations for a current RFS trial of "predetermined dispatch of an aircraft".

"We were able to have that plane launched and flying in a shorter period of time than if we had followed previously established protocols," Mr Stewart said.

Earlier:

Almost 2000 residences and businesses around Wagga are without power, with 1332 customers from Gumly all the way south to Book Book blacked out.

Another 313 are affected in North Wagga, 90 in Kooringal and 78 more west of Uranquinty are also impacted.

Trains on the nearby line have been stopped from going through as firefighters work to contain the fire.

The fire is currently at advice level, thanks to the quick response of three RFS crews and support from Fire and Rescue NSW.

"We are currently responding with trucks, we've also dispatched aircraft immediately to this fire," Ben Shepherd from the NSW RFS said.

"We have had some lightning and strong winds move through the area."

"Three RFS and FRNSW crew have managed to get upper hand on that," Mr Shepherd said.

"There were some concerns initially given the erratic and gusty winds through the area but that fire is going to remain at advice.

"There is also a further small fire as well... but also crews are confident around getting around that."

A severe thunderstorm warning for damaging winds was issued for a large part of the Riverina shortly after 1.30pm on Tuesday, with gusty winds arriving in the city within an hour.

A wind gust of 87km/h was recorded at Wagga Airport at 3.17pm.