The Health Information and Quality Authority has issued a residential service run by Rehabcare with a notice proposing to cancel its registration.
The move follows an inspection of the facility in Co Limerick known as The Glen, which failed seven of the nine regulatory tests applied.
It found that an over-reliance on relief and agency staff resulted in residents not receiving the consistent care they needed.
At the time of last May's unannounced inspection, The Glen was home to four male and female adult residents who required a high level of staff support to meet their assessed needs.
The rural centre had no vacancies and comprised a domestic style two-storey building on a spacious site.
Today's report states that residents' needs were incompatible and that the absence of a comprehensive assessment of their needs was a significant failing.
It notes that Rehabcare had acknowledged "longstanding complexities and challenges" in the service but that there was inadequate oversight, including clinical oversight, to ensure that residents got consistently safe and high quality services and supports.
Inspectors were not satisfied that Rehabcare had completed a programme of staff training that it had identified as necessary three months earlier.
The report states that records showed that allied health services had been provided on a one-off basis with no clear arrangement in place for follow-up, re-referral or monitoring of the success or otherwise of recommendations.
But it exempts psychiatric and behaviour support services from this criticism.
The Glen failed seven of the nine regulatory tests applied and was moderately non-compliant in the other two.
In the wake of the inspection HIQA issued Rehabcare with a notice proposing to cancel the centre's registration.
The provider was given the statutory 28 days to respond and HIQA says that process is in train.