More than 20 inmates were locked out of Limerick Prison this week after being returned there from court.
In an unusual twist, five vans carrying prisoners were stopped from going inside the main gates because of ongoing industrial action.
These images show the prison service escort vehicles queuing up outside the compound on Tuesday night for some time.
Prison sources said similar scenes would have been spotted around most of the major prisons after staff withdrew all goodwill measures.
It is understood an unofficial nationwide work-to-rule has been in place in prisons nationwide in recent days amid claims that are being made work an extra 20 minutes at the end of their shift.
Officers also maintain that a eduction in overall staffing levels is affecting the secure and safe control of prisoners.
However all issued were resolved at the Labour Relations Commission yesterday, the Prison Officers' Association confirmed.
The Irish Prison Service would not comment on the matter, but confirmed the industrial relations issues had been before the LRC