Two prisoners have climbed on to the roof of Cloverhill prison as part of a protest.
The Irish Prison Service confirmed 10 inmates at Cloverhill in west Dublin were initially involved in the dispute by refusing to leave an exercise yard and return to their cells.
Another 50 prisoners remained outside during the stand-off but are not believed to be actively involved in the protest.
A spokesman for the service said two men scaled a wall to take the protest to the roof.
“The staff are managing the situation. Two guys have got up on the roof but there is no threat of escape,” the spokesman said.
The exact reasons for the prison protest have not been revealed.
Cloverhill is part of the west Dublin prison campus which also incorporates Wheatfield and it is primarily used to house prisoners who are being held on remand.
The protest was taking place in the yard for the B division of Cloverhill.
Prisoners in the adjoining Wheatfield complex were understood to be in lock down as management made arrangements for additional staff to be brought across to the Cloverhill wings.