NSW Corrective Services is investigating an 'incident' at Goulburn Correctional Centre that occurred on Thursday.
A Corrective Services spokesperson said unrest began on Thursday afternoon when a number of inmates 'refused to obey directions to leave their yards as per normal routine'.
"About 5pm, gas was deployed in one of the yards to remove approximately 12 inmates, who were then safely returned to their cells," the spokesperson said in a statement.
"By 6:45pm, the majority of involved inmates had complied with directions and were safely returned to their cells.
"About 7pm, chemical munitions were used to secure five remaining inmates who had failed to comply with directions."
The spokesperson said a number of inmates climbed onto shade awnings in some of the correctional centre's maximum-security yards.
They said there had been no fires or weapons involved and only minor property damage. One inmate was being treated for minor injuries on site.
Corrective Services Commissioner Peter Severin commended the officers' response and 'skilful handling' of the incident.
“Corrective Services officers face a difficult job each day in managing some of the most challenging people and situations,” he said.
“It was managed carefully and professionally, without injuries to staff. Well done and thank you for continuing to keep the community safe.”