Gardaí refused to give Tusla details of interviews with two children who were allegedly raped, it has emerged.
The finding is included in the latest study from the Child Care Law Reporting Project (CCLRP), which also revealed a lack of co-ordination between State services dealing with children.
Other examples include a lack of places for children who are described as "dangerous".
Director of the CCLRP, Dr Carol Coulter, said that there are a number of issues that keep recurring before the High Court.
"The High Court is showing, again and again, how difficult it is sometimes to find placements, and how inadequate the provision is of placements for children who do have very challenging behaviour," she said.
"They’re usually teenagers, it has to be said on the whole these are not young children, and they’re children with mental health and behavioural problems."
- Digital desk