Fire and Rescue NSW (FRNSW) crews have extinguished a fire which damaged a grain silo at Condobolin last night.

The blaze broke out around 8pm in a loader vehicle, inside the concrete structure, at a major grain storage facility on Silo Road.

FRNSW quickly deployed eight firefighters and two fire trucks to the scene, including specialists in hazardous materials response.

The NSW Rural Fire Service provided additional crews in support.

They were confronted by large flames which were impacting the silo, containing up to 4,000 tonnes of wheat, and the system used to load the crops into it.

Twelve workers were evacuated from the area, while a train stationed near the silo was relocated as a precaution.

Fire crews began attacking the blaze from outside the silo due to concerns of a possible dust explosion, and low visibility caused by thick smoke cover.

They ventilated the structure before firefighters, wearing breathing apparatus, safely moved to further douse the fire from an open entrance to the silo.

The fire was extinguished after more than five hours of attack.

Smoke is expected to linger around the site for the next 24 to 48 hours.