Most of a prison wing that accommodates nearly 100 prisoners in Cloverhill Prison, Dublin, has been cleared to free up cells in case large numbers of protesters are detained during the upcoming May Day demonstrations.
Special sittings at the prison's courthouse have also been planned - the court does not normally sit at weekends.
The prisoners have been transferred from the wing in recent days, mainly to Wheatfield Prison.
While Cloverhill always has some spare bed capacity to cater for an influx of remand inmates, the Garda has requested the Prison Service to ensure a much larger number of spaces than usual are free.
The request forms part of a massive security operation in Dublin this weekend, which will involve more than 5,000 gardaí and over 2,500 soldiers. Gardaí will this morning put on display two water cannon vehicles borrowed from the Police Service of Northern Ireland for use if necessary.
The Garda Commissioner, Mr Noel Conroy, said yesterday that intelligence suggests between 250 and 300 international protesters visiting Dublin will try to cause a disturbance at, or near, celebrations to mark the entry into the EU of 10 new member-states.
"I can tell you that from the information we now have in our possession that they will definitely try to cause a disturbance on the day," he said.
"It is a day for celebration, but we are also aware of intelligence we have generated ourselves and also from other police forces that there are a certain amount of people coming that will cause problems and there's no doubt about that.
Mr Conroy continued: "We are aware of a number of people who will be demonstrating on the day, and indeed demonstrating peacefully, but the information we have is that some of these people that are coming into the country may very well mingle with those people who wish to protest in a peaceful manner, and may cause them to become involved in a situation none of us would like.
"Some weeks back we were looking at various Internet sites, and also from information we are getting from a particular country we expected numbers to be pretty big. But I can say that that doesn't seem to be panning through. The numbers of problem people who will be coming will be smaller than anticipated. We'd be talking about 250 to 300 people."
Mr Conroy said these will mostly be from Britain but continental countries would also be represented. "We will monitor their activities as closely as we can. And we will be receiving some assistance from other police forces in relation to the identification of those people. If they break the law within our sight you can take it they will be dealt with quickly and efficiently.
"We will be policing in the way we normally police any demonstration conducted in a peaceful manner."