Minister for Health Mary Harney has said she requested the resignation of the former chairman of the Children's Hospital Development Board.
Former chairman Philip Lynch pinpointed funding issues and planning challenges at the site as the reasons for his resignation last week.
In a statement, Mr Lynch says that unless substantive issues were addressed, the successful delivery of the new children's hospital in Dublin was at serious risk.
Mr Lynch also said that he resigned because he and Minister Harney differed on a number of significant and fundamental issues.
He said his concerns included the 'substantial funding gap and planning and design challenges for the Mater Hospital site.'
Mr Lynch said if these and other issues are not addressed the new €650m hospital, wherever it is located, will be put at risk.