If they are causing a public nuisance then call the Gardai.
Been there, done that etc. The Gardai, while being very understanding, have informed me that all they can do is ask the people to keep things down. (The fact that they are guardians of the peace is not quite as literal as some - including me - would like. If, for example, I were to threaten to smash a few windows to try to get my noisy neighbours to understand that they are driving me crazy, then the Gardai would have to arrest me, not the neighbours who are making the noise which is driving me crazy in the first place.)
Try phoning the prtb, I phoned on behalf of a Czech friend who was being cheated by an Irish landlord, and they were really helpful. I don't see why they wouldn't be helpful in a reverse situation.
My story may be somewhat useful. As it happens, some Polish people renting a house about 50 yards away from mine have been blaring music through open windows on a regular basis in recent weeks. It finally got to me a few days ago when it was coming in through my double glazed windows, so I called around, smiled politely, apologised for the intrusion, and explained that the music was coming in to my house even through the windows, so could they keep it down a bit please.
The woman I spoke to said "sorry, I'm so sorry, really sorry, sorry, oh I'm sorry ... " and I thought that's grand, she obviously didn't realise how loud she had the volume up. Five minutes later and I realised she was just a smarmy lying "insert your own word here". Two and a half hours later and I knew for sure she didn't give a damn about her neighbours.
My camera has a video function (with sound) so I've been out a couple of times getting a half minute or so of evidence just in case it's needed down the road. Obviously I hope not, I would just rather a quiet life at home.
I was fairly sure I knew who the letting agents were (I used to be very friendly with the houseowners, but they moved abroad over 10 years ago), so phoned them on Monday and explained what was happening. The letting agent said that a letter would be in the post to the tenants that day.
There was lots of noise Monday night (got video to prove it) but I think the letter might have been received Tuesday as it has been quiet since.
Fingers crossed.
http://www.environ.ie/en/Environment/NoisePollution/
This link gives info about noise nuisance being caused by people in private rentals. Basically, someone renting a property is obliged not to engage (or allow guests to engage) in behaviour which interferes with the peaceful occupation of other dwellings in the neighbourhood. The Residential Tenancies Act 2004 imposes an obligation on landlords to enforce the tenant obligations. Complaints may be referred to the prtb.
Good luck.