The former chairman of Wales' biggest health authority has urged there should be a police probe or public inquiry into a damning audit report into its finances.

Mark Polin, retired chief constable of North Wales, had been asked to resign with other independent members of  Betsi Cadwaladr health board  at the end of February after the Welsh Government had returned the authority to special measures.

Yet it was the frustrated chairman and his colleagues who had demanded the explosive report into the financial running of the organisation.

It alleges changed documents, cover-ups involving millions of spending and problems hidden from board members.

A fraud inquiry has apparently concluded that no personal gain was involved. 

Mr Polin said he was astonished that First Minister Mark Drakeford had told the Welsh Senedd last week that he had not read the audit report.

Mr Drakeford had claimed that it should be kept under wraps in fairness to those criticised, who may have to answer to a disciplinary inquiry.

Last autumn, when Mr Polin was re-engaged for a further term as chairman, the First Minister had remarked: "We are lucky to have him."

Mr Polin suggested on Monday: "Someone needs to examine the circumstances behind the NHS Counter Fraud Wales decision not to continue with their inquiry.

"But really these are matters which should be pressed by politicians. It is up to them, not myself."

David Jones, Tory MP for Clwyd West, said: "Police should become involved. There are so many troubling issues raised in the report."

A spokesman for the health board said: "The management of the issues raised in the Ernst and Young report is progressing in line with existing procedures and policies. It is inappropriate to comment on the status of any employees at this stage." 

Betsi has nearly 19,000 employees - and there have been bitter complaints that hard-working nurses and doctors are being let down by those in charge. 

On Monday night, Detective Chief Superintendent Gareth Evans of North Wales Police said: "We are aware of media reports regarding financial matters at Betsi Cadwaladr University Health Board and have also had concerns raised with us by individuals.  

"We are liaising with colleagues in other agencies regarding enquiries already undertaken in order to make an assessment and will issue an update in due course."