Three prison officers were injured and hospitalised after an attack by two inmates in Mountjoy prison on Sunday.
One officer was head-butted and suffered a broken nose, another punched into the side of head and another had their finger dislocated during the incident on the B1 landing.
It is understood prison staff had liquid poured on top of them by prisoners on the upper tiers during the incident.
The inmates are aged 21 and 30 and are from Dublin. They are serving sentences for armed robberies.
Gardaí and the Irish Prison Service are investigating the incident.
An Irish Prison Service spokesman said they would not comment on the individuals involved and the investigation was ongoing.
“They’ll certainly face internal disciplinary procedures from prison service, whether or not criminal charges are brought against them is a matter for guards,” he said.
In April, two prison officers were injured at the jail after a prisoner used a shiv, or a homemade knife, to attack them.
One of the officers received a stab wound to the head while the second sustained wounds on his back and chest.
The spokesman said in the last year there were about 140 attacks by inmates against prison officers nationally.
“Obviously we do everything we can to protect our staff in an environment where we have a lot of criminals the potential for violence is always there.”
Prison Officers Association deputy general secretary Jim Mitchell said it was not acceptable for people to come to work and be injured .
“It’s just another one in a litany of assaults on our members from the start of the year. For us it is not acceptable,” he said.
Mr Mitchell said there needed to be a deterrent to stop prisoners attacking officers.
“There should be legislation that is absolutely clear cut. We need automatic consecutive sentencing,” he said.
“It’s nearly like ground hog day for prison officers. There’s a huge feeling within prisoners that they can act with impunity.”
Mr Mitchell said the same names of prisoners kept coming to their attention for attacking officers.
“The sanctions don’t seem to be working. It’s worse now than it’s ever been,” he said.
“Don’t put prison officers in harms way. There needs to be an automatic consecutive sentence for an assault on a prison officer.”
