The HSE has asked the St Vincent's Healthcare Group to confirm that all "irregular" payments to senior staff have now stopped.

In a letter sent last week, HSE director general Tony O'Brien sought assurances that no public hospital employees were in receipt of any additional or irregular payments from either the public hospital, St Vincent's Private Hospital or any associated entity within the overall St Vincent's Healthcare Group.

The St Vincent’s Healthcare Group, which runs the public St Vincent’s University and St Michael’s hospitals in south Dublin as well as St Vincent’s Private Hospital, has in the last year or so been at the centre of controversy over top- up payments for senior executives, governance arrangements and provisions that allow consultants with public hospital contracts to work in its private institution. The HSE provides €200 million in annual funding for the public hospitals in the group.

In the letter, Mr O’Brien also looked for “confirmation of the segregation of governance, management and financial arrangements in respect of the University Hospital including full detail of the schedule of delegation which underpins this”.

In the letter, which was sent to the chief executive of St Vincent's University Hospital Kilian McGrane and the chairman of the St Vincent's Healthcare Group James Menton, Mr O'Brien also sought assurances "that full disclosure has now been made in respect of any and all breaches of public pay policy in the hospital".

Last month the HSE expressed its unhappiness at learning that the former chief executive of the St Vincent's Healthcare Group Nicky Jermyn, who left the organisation last summer, had been reappointed to a new post of director of strategy. The group said it would fund Mr Jermyn's new post from its own resources and there would be no charge on HSE finances.

The HSE said last month in response to reports of Mr Jermyn’s appointment: “Should this be the situation, it is not in keeping with the constructive relationship developed between the HSE and St Vincent’s Healthcare Group over the past year. Such an appointment at this juncture would have implications for any future positive relationship between the HSE and the group.”

A HSE spokesman later said it had taken a considerable period to disentangle the confusion and complexity surrounding the governance and operational relationship between the HSE and the group. There was concern the appointment would perpetuate that confusion.

In late 2013 the St Vincent’s Healthcare Group became embroiled in a controversy with the HSE and the Dáil Public Accounts Committee over whether it was compliant with public service pay rules.

Just before Christmas 2013, the St Vincent’s Healthcare Group said Mr Jermyn was receiving a package of more than €292,000 a year. It said this was made up of €136,282 from the public sector and €136,951 from the private sector, as well as a privately funded car allowance of €19,796.

The group came under fire from the HSE and the Dáil Public Accounts Committee over the payment of additional sums to senior executives, over and above official public health service-approved salaries, for work in its private hospital.

The Irish Times reported last month that St Vincent's Healthcare Group was in contact with the Revenue Commissioners about the possible tax implications of an arrangement under which a senior executive was provided with accommodation and had utility bills paid for by the organisation.

The hospital group also said that between 2006 and 2011, five of its senior executives had private health insurance subscriptions reimbursed subject to normal tax rules and deductions. It said the reimbursement had not been funded from public money or charitable donations.