A fire in a grain silo at Wallaroo has been contained by fire crews, and an 800 metre evacuation zone around the area removed.

Metropolitan Fire Service (MFS) crews were called to the silo fire just before six o'clock Thursday morning, after the blaze broke out in the gantry section of the silo.

CFS and SES volunteers are also on the scene.

Fire crews say it has damaged the gantry, the structural framework connecting the grain storage areas of the silo.

An 800 metre exclusion zone and 4000 metre aerial exclusion zone were established around the silos as a precaution.

"MFS firefighters and CFS volunteers are using thermal imaging cameras to determine whether there are pockets of heat which present a risk of fire," MFS Commander Greg Crossman said earlier on Thursday.

"The exclusion zone will not be reduced or cancelled until we are satisfied the area is safe."

250 people were evacuated from their homes and were waiting at the oval at Wallaroo with support crews.