The Health Service Executive (HSE) is to review care standards for 4,500 foster children after an independent report raised serious concerns over gaps in the system.
The first report by the Social Services Inspectorate into a HSE fostering service in the north east found one-third of all children did not have a dedicated social worker.
Inspectors said they were "extremely concerned" because this meant standards for the assessment of children's needs and care planning for young people in foster care could not be met.
They also raised concerns about the child protection system, relating to the way disclosures made by children were assessed and the frequency of social work visits.
In order to ensure national standards for foster care are being met in all HSE regions, the inspectorate has called on health authorities to audit the status of all child protection concerns of children in foster care. It also says there needs to be emergency out-of-hours support service for children in care.
Despite these shortcomings, inspectors said they found evidence of good practice in many areas and were impressed by the care the children were receiving. Many of the children felt well cared for and were happy in their placements.
Staff shortages were causing delays in processing the applications of foster carers to adopt their foster children, while some children in foster care were not able to see their birth families regularly.
The report shows that a principal social worker in Co Meath requested 21 staff posts to help reduce the level of potential risk to children. To date, approval had been given for six extra workers.
A spokesman for the HSE said last night that it strived at all times to adhere to the highest standards and best practices for all children in care. He said many of the issues raised in the report were mentioned in the national standards for foster care, which outline best practice, protocols and standards.
"The HSE has committed to carrying out a thorough review of these standards in 2008 in order to ensure that they are being implemented and adhered to," the spokesman said.
On the recommendation to establish an out-of-hours service, the HSE said it has commenced detailed discussions with trade unions and other relevant bodies with a view to commencing this service in 2008.
The Irish Association of Social Workers said yesterday that the failure of health authorities to fill vacant social work posts and to recruit new social work staff was putting vulnerable children at risk.
Its spokesman, Declan Coogan, said: "It seems that the protection of children is at the bottom of the list of priorities of those who make decisions about funding but are remote from the consequences of these decisions."
He said many social workers in child protection services experience stress, burn-out and exhaustion as they struggle to respond with inadequate resources to an ever-increasing need.