Maximum security inmate starts NSW prison riot

A maximum security inmate has started a fire and sparked a riot in a NSW prison.

Tear gas was deployed to control the situation when the South Coast Correctional Centre in Nowra was put in lockdown about 9.30am.

The fire was ignited by a prisoner who refused to leave his cell.

Guards fired teargas when two other inmates climbed on to an awning.

Civilian staff were evacuated from the site and additional correctional officers were brought in to secure at least 60 inmates. 

"A number of smaller fires were lit in additional cells. Once that had occurred the prison was placed in lockdown," Brad Collins from the Royal Fire Service told 9News.

"I believe there's been very minimal damage, as I said the cells are constructed of concrete and a basic mattress type situation."

Prison staff extinguished the fire shortly after and treated several people for minor smoke inhalation.

Corrective Services NSW Commissioner Peter Severin said all inmates were now secured in their cells.

He commended the corrective services officers for their swift response.

"Officers face a difficult job each day in managing some of the most dangerous people," Mr Severin said in a statement.

"They did a terrific job," he added.

Corrective Services NSW will investigate the incident. The inmates involved could face criminal charges.