The head of the Irish Foster Care Association is blaming a high staff turnover for any potential failure to report abuse allegations.
Breda O'Donovan has said children are not remaining with social workers long enough to feel comfortable telling them about problems.
Her comments follow an RTE Prime Time report which found children were left in a west of Ireland foster home for years, despite allegations of sexual abuse against a family member.
Currently 7% of children in care don't have a social worker assigned to them - that equates to 451 children.
Ms O'Donovan has said it takes time to win children's trust: “There’s a huge turnover of social workers there.
“Then children don’t build relationships with their social workers, so if there is an issue for them they are going to find it very hard to go and talk to anybody because they don’t have a relationship with the social worker.
“You would hope that they would have a relationship with the foster carer, but every relationship is different.”