There is a risk that special measures status of a north Wales health board 'may have become a normal state of affairs' according to a committee of AMs.
A report by the Public Accounts Committee into the running of Betsi Cadwaladr University Health board criticises the pace of change and the attempts by Welsh Government to lift it out of special measures.
The report says Welsh Government support has been 'insufficient' and that actions 'had little practical impact' on changing the health board's performance.
The review paper says: "It is simply unacceptable that BCUHB [Betsi Cadwaladr], as the largest NHS body in Wales, has been in special measures for nearly four years."
The committee says: "We share the frustrations of the people of north Wales at the pace of change and believe that both patient input and clinical engagement in delivering change has not been as effective as it could be."
The report also takes aim at the health board's leadership saying it is 'deeply concerned' that it has "failed to grip its financial position" and that recurring deficits are 'unsustainable'. It adds that "poor quality savings plans the Board has had in place...have been both simplistic and overly ambitious."
While the report does highlight areas where the health board is attempting to make improvements, the report says that in some cases it is too early to say whether changes will have the desired impact.
The health board was put into special measures in 2015 following concerns around mental health care and findings of 'institutional abuse' of patients. A later report said it found no evidence of such abuse.
Under the special measures arrangements the Welsh Government has provided managerial and advisory support to the Health Board and over £80 million of additional funding.
In response they say they will review the committees report and will respond fully in due course".