Emergency action was taken to protect children in foster care in Co Mayo earlier this year after the Health Information and Quality Authority found a number of them to be at immediate risk of harm.
A report shows that inspectors took, what HIQA calls, "exceptional regulatory" measures after an announced inspection of foster care services in April.
It says that not all children were safeguarded and protected from potential harm and that the local health authority only met five out of 27 standards of practice.
If found that children were placed with inappropriate carers, the HSE local authority had failed to recruit and retain an appropriate number of carers and that there were no special foster carers.
The report says that in some cases the foster carers were not always removed from the foster carer panel promptly when allegations against foster carers had been upheld.
It found that there was the potential that some carers, who had been removed from a panel in Co Mayo, could provide foster care in another local health authority because information might not be properly passed on.
HIQA found that the local health authority did not ensure that foster carers received proper training and that there "was not sufficient leadership and commitment to the delivery of effective foster care service".
Another report, detailing an inspection of care services in Waterford, found 397 children were still waiting on initial assessments and 31 children awaiting further assessments.
A HSE West spokesman has said that deficiences in its foster care system in Mayo have been addressed and all children are fully safeguarded.
Speaking on RTÉ’s News At One, Garry Kiernan, specialist in children and family services for HSE West, said the local health authority had fully co-operated with the inspection and had acted on its findings.
Mr Kiernan said the health authority had put an action plan in place, including making its reporting procedures more child-friendly.
He said deficiencies in the training of foster carers, as highlighted in the report, have been addressed.
Mr Kiernan said HSE West welcomed the report and had brought in external consultants to review their procedures.