There were initial fears up to 50 inmates may have been involved, but police later confirmed there were only about 12, with two inmates acting as ringleaders.

The drama began at around 1.30pm when an inmate became argumentative with jail staff and refused to leave a maximum security wing at the jail.

As the inmate was restrained, another inmate attempted to intervene by striking an officer in the head a number of times.

The Immediate Action Team was called to the wing and took charge of the two inmates.

A spokesperson for Corrective Services said as the officer was being taken to the clinic for treatment, inmates in the yards became unsettled and began calling out abuse.

As a result, the inmates were secured in their cells, but a number of inmates in two yards refused to comply and chemical munitions had to be deployed.

The spokesperson said the ringleaders of the incident were subsequently being held in segregation.

The officer who was injured in the incident received treatment and was offered counselling.

NSW Police, Fire and Rescue and ambulance officers also attended the centre in case of further problems.

Chifley Local Area Command duty officer Inspector David Abercrombie said the role of police was to monitor the facade of the jail, in case the situation escalated.

Inspector Abercrombie said a number of inmates threatened to start a fire, and incited others to do the same.

He said while there wasn’t actually a fire lit during the incident, the fire brigade was on standby as a precaution.

Inspector Abercrombie confirmed there were about 12 inmates involved in the fracas, all of whom were quickly contained by Corrective Services staff, although verbally they continued to be non-compliant.

He said the situation was contained just after 4pm and there was no need to bring in Chifley’s specialist tactical operations unit.

“It was contained using local resources; our role was literally to monitor the situation in the event it escalated.

“Corrective Services handled the internal situation.”

NSW Corrective Services Commissioner Peter Severin praised staff and the Immediate Action Team for what he said was their effective and judicious handling of the incident.

Investigations into the incident continue.