Concerns were raised over foster care standards in Mayo 16 times in one year, a health watchdog has disclosed.
Health chiefs in the county were forced to take radical action to protect some children after inspectors feared a number of them were at immediate risk from abuse.
The Health Information and Quality Authority (Hiqa) stepped in and ordered the exceptional move and claimed the Health Service Executive (HSE) response had been inadequate.
Hiqa said it found 16 concerns about the welfare and protection of children in eight foster care families in the 12 months to April this year.
It said the HSE had delayed its response to early warnings of possible abuse in foster homes for a small number of children.
"The decision to issue an immediate action plan is an exceptional regulatory activity which is used when inspection findings indicate that there is an immediate risk to the welfare of children and young people," it said.
There are 123 children in 107 Health Service Executive (HSE) foster homes attached to authorities in Mayo - 32 children with a relative; and 91 in general foster care, including 10 outside the area.
Inspectors reported concerns that a small number of children might not be safe and that some c hildren experienced unsafe placements for a significant period of time.
Overall the Hiqa report found that health chiefs in Mayo d id not have effective systems in place to ensure safe and effective foster care.
It warned that some foster carers were not always removed from the panel promptly after complaints were upheld against them and others were not properly vetted.
Its inspection of the Mayo foster system found only five of 25 standards had been met in full.
Inspectors found children did not fully understand what their rights were and some felt they were not being consulted and included in decisions about their future. It also found complaints were not addressed in a child centred manner.
Some carers warned that there was a lack of training to deal with children who had suffered trauma or displayed challenging behaviour.
The report revealed:
:: Foster families were recruited from the travelling community but no other ethnic or cultural minority groups.
:: One child who spoke with inspectors did not have knowledge of his/her own culture.
:: Social workers did not know how to make a protected disclosure, a method of whistle blowing whereby staff are protected if they flag up concerns about services.
:: Foster carers said they used instinct rather than guidance from social workers on what, if any, child protection concerns should be reported.
:: Only four out of 107 foster carers got child protection training last year and a majority of those questioned by Hiqa did not know about the statutory Children First protection measures.
:: About one-third of children in foster care did not have a timely child-in-care review and two were not reviewed for two years.
:: Poor and or strained relationships between some foster carers and children and the social work department were uncovered, leading to insufficient monitoring.
:: The names of foster carers removed from the panel were being recorded alongside others who had stopped fostering for other reasons or were facing allegations.