Miles' comments came after Conservative health spokesman James Evans raised the departure of David Donegan, chief executive of Velindre NHS trust, in the Senedd. Donegan left his role at the end of November, a year after starting.

Evans said: ‘Recent media reports have suggested that the CEO of Velindre University NHS Trust was removed from the job after only a year in post after raising concerns about governance arrangements in the NHS Wales Shared Services Partnership and that the chair of the trust's term was also not extended past her four-year term, which is very unusual, and she also raised similar concerns regarding the NHS Wales Shared Services Partnership.'

He added: ‘Given the alleged irregularities within the shared services partnership in respect of governance, and the sudden departure of the chief executive of Velindre NHS Trust, reportedly because he began to investigate these issues, serious questions arise about what senior leaders and ministers within the Welsh Government knew and whether these problems were being kept out of sight or individuals sidelined to avoid reputational damage for the government.'

Evans called for details of any correspondence or ‘whistle-blowing concerns' relating to alleged criminality within the shared services to be published in full.

In response, cabinet secretary for health and social care Jeremy Miles, said in a statement: ‘I would like to address the allegations that have been made concerning criminal activity within [NHS Wales Shared Services Partnership] NWSSP. I want to state unequivocally that Welsh Government has neither seen nor received any evidence to suggest criminality.'

He explained that an independent review of NWSSP's governance and accountability arrangements was commissioned in April and its recommendations and response will be published.

Miles said: ‘The review engaged Velindre, NWSSP, and other NHS stakeholders. The recommendations were shared with the chairs of Velindre and the Shared Services Partnership Committee, who have shared their joint feedback.

‘The final recommendations and response will be published to ensure transparency, and implementation will follow, through a collaborative programme between both organisations and Welsh Government to strengthen governance and accountability.'