Emergency services from across the region rushed to High Street in Hillston around 3.30pm, where they found smoke streaming from a burning building and flames threatening the premises next door.

"On arrival [firefighters] found a large volume of smoke and flames coming from the rear of a local business," Fire and Rescue NSW's [FRNSW] Leeton-based duty commander Matt Hunter said from the scene.

"In the main building, due to it being an antique shop with a large amount of bric-a-brac and items, the fire took hold quite quickly.

"With the assistance of the Rural Fire service we were able to stop the fire from doing significant damage to the neighbouring building."

The fire had reached a shared ceiling in the adjacent shopfront, which sustained damage from the ensuing firefighting effort.

"The main [shop] where the fire occurred is pretty much totally destroyed," Mr Hunter said.

"All the items in the shop have been either heat, smoke or water-damaged, and there's some damage to the adjoining building just from firefighting efforts to stop the fire spread."

Hillston's FRNSW crews were supported by colleagues that travelled up to 150km to assist in bringing it under control, with 25 FRNSW personnel on site along with police and NSW Ambulance teams.

"Crews got to work straight away and called in resources from around the area, from as far away as Hay, Griffith and Leeton," Mr Hunter said.

It took an hour to bring the fire under control and almost five more for crews to wrap up the firefighting effort, with the street reopened to traffic around 8.30pm.

Firefighters were set to remain at the scene overnight to monitor the debris. How the fire started is yet to be determined.

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