A significant number of foreign youngsters placed with foster families in Ireland have had a bad experience.
When 21 children were interviewed for a report by Barnardos and the Health Service Executive (HSE), researchers noted claims that some were underfed, physically abused and screamed at by some carers.
The study revealed that at least a third of asylum seeking children separated from their family subsequently experienced a placement breakdown while in a foster home.
Mary Kenny, manager of the HSE's national office for unaccompanied minors, said a general lack of foster carers meant it was harder to match children to suitable families.
She said: "The most important thing with matching a child with a family - culture is important - but most important is that it's an emotionally stable situation. The match with a family is more important than geography. The actual match with the family is the key piece."
The report, entitled Foster Care and Supported Lodgings for Separated Asylum Seeking Young People in Ireland, found foster placement breakdowns happen for many reasons including behavioural problems, a lack of support for carers, rivalry between the foster child and the host family's child, foster parent stress and burnout.
When they occur, they can be hugely upsetting for young people and their carers alike, the report said. Author of the report Muireann Ni Raghallaigh, of UCD's School of Applied Social Science, said more foster families are needed in Dublin.
"While foster care and supported lodgings are working well for the majority of young people, one of the clear findings of the report is the need to ensure that the care offered reflects the individual needs of each child," she added.
While the report highlighted an "urgent" need for more foster carers across Ireland and with more diverse backgrounds, Ms Kenny said it was not always best to place youngsters with families of the same ethnic origin.
She said it was important to ensure a child was exposed to their own culture, through festivals, community groups and food. But she added that it was sometimes more helpful to place them with a family from a different background which could help them better integrate into Irish society.