An inspection of the Ballydowd Special Care Unit in Dublin has highlighted problems with some of the care provided to young people there.
Officials from the Health Information and Quality Authority visited the facility, unannounced, in July after someone raised a concern about the practice of "single separation".
The practice is supposed to see a seriously disruptive young person isolated "for as short a period as possible" to give them an opportunity to regain self-control.
However during their inspections at Ballydowd, officials found that some children were locked in rooms for unnecessarily prolonged periods, some had no access to toilet facilities or showers, and some remained overnight in secure rooms without mattresses.
Responding today, the Child and Family Agency Tusla said it accepts that the processes underpinning the use of single separation were not adequate.
It has expressed regret over this and said it is currently taking steps to strengthen its decision-making procedures and facilities.