Prison officers at Mountjoy jail are to ballot for industrial action.
The move follows a meeting today of over 160 officers.
Staff at the jail said they were worried about the overcrowding problem and their own safety.
The officers were also aggrieved at the comments of the Director General of the Prison Service, Brian Purcell, who insisted there was not a crisis in the prison system.
The POA said prison officers feel management have 'their head buried in the sand' in relation to the ongoing problems which has manifested itself in a series of violent incidents in the country's jails.
