The Chair of the National Paediatric Hospital Development Board Tom Costello has announced his resignation this morning.
The board is responsible for overseeing the building of the new National Children's Hospital which could cost as much as €2bn.
Mr Costello was appointed to the board in 2013 by the former Minister for Health James Reilly.
In a statement today, Mr Costello said that he was concerned that the attention placed on the cost of the hospital was causing "reputational damage" to the project.
He said he was stepping down in order to help ensure that the focus is returned to delivering the project.
"I am concerned about the reputational damage that the ongoing commentary about the increased cost of the hospital is having on this critically important project and so I have decided to step down from my role to help ensure that focus is restored on delivering the project," he said.
Mr Costello said has acted with professionalism and integrity during his time as chairman, and that every decision made by the board was guided by "what was deemed best for the project".
He said that since he had taken up the role six years ago, he worked " with the sole objective of ensuring that children and families in Ireland finally get the new children’s hospital that they badly need and deserve".
He said the project has "achieved many significant milestones" with the hospital set for completion in 2022.
Mr Costello paid tribute to the board members, saying "they have been asked to make extremely difficult decisions and have done so at all times in order to ensure that the hospital is built, and the delivery of paediatric care in Ireland can be transformed".
He wished all those involved with the project the best for the future.
Mr Costello, a Chartered Engineer and Fellow of Engineers Ireland, runs a project management consultancy business and is a former Managing Director of John Sisk & Son Ltd.
Minister for Health Simon Harris accepted Mr Costello's resignation, and thanked him for his "exceptional commitment to the project for the past six years".
Yesterday, a review of the rising costs of the National Children's Hospital was told not to find any individuals to blame.
The terms of reference for the review of the project revealed that the independent review would “stop short of determining culpability at the individual level".
The current figure for the cost of the hospital now stands at €1.7bn, with the final price tag having the potential of exceeding €2bn.