Minister for Public Expenditure and Reform Michael McGrath has expressed concern over the progress of the National Children's Hospital project to Minister for Health Stephen Donnelly.

In a letter to Mr Donnelly last month, obtained by RTÉ's Morning Ireland under Freedom of Information, Mr McGrath points out that since July of last year the Government has been waiting for a definitive update on the project from the Department of Health and the National Paediatric Hospital Development Board (NPHDB).

The NPHDB is responsible for overseeing the building of the new hospital.

Mr McGrath said the lack of an update "gives cause for concern", adding that an 'options paper' that "has been in development by the NPHDB for some time" has not materialised and clarification is "urgently required".

In the letter dated 4 February, Mr McGrath also referenced the then-recent resignation of the chair of the NPHDB, Fred Barry (who eventually left his role at the end of February), and said the fact this leaves five vacancies on the NPHDB is not "an acceptable or sustainable position".

"These vacancies must be impacting on the ability of the Board to function at the required level and should be addressed urgently," he added.

In relation to the number of vacancies on the NPHDB, the Department of Health said the "immediate priority" for the Minister for Health is finding a permanent replacement for the previous chair, Mr Barry.

It added that "in the meantime" vice-chair Tim Bouchier-Hayes has been appointed as Interim Chair.

On 23 February, the Minister appointed Brian Keogh and Michael Barry to the NPHDB, which left three vacancies on the board.

The Department said a panel for the "subsequent selection of ordinary board members will be established as soon as the new chairperson has been appointed".

Mr McGrath also asked Minister Donnelly to keep him fully up to date with the ongoing monitoring of the NCH project, and wrote that an "urgent update on all aspects of the project should be brought in a Memorandum to Government as soon as possible", which would include latest estimates for the cost of the project, as well as a realistic timescale for delivery.

In response to this, the NPHDB said it has completed a "detailed analysis of the project timeline" that "is currently being considered by the Department of Health".

While the Department said it is "the Minister's intention to bring forward a Memorandum for Government in the coming weeks, once this has been reviewed by Department officials and the Minister himself.

"Minister Donnelly expects to be in a position to provide an update on the project to all Cabinet colleagues, including Minister McGrath and the Department of Public Expenditure and Reform."

On 9 February, five days after Mr McGrath's letter to Mr Donnelly, the Public Accounts Committee heard that the construction of the new children's hospital had been delayed again and it might not open until 2024.

NPHDB Chief Executive David Gunning also told the committee then that he could not give guidance on whether the final cost of the project would exceed €2bn.

The hospital was previously expected to cost €1.4bn to build with another €300m for equipment and IT.