A new Children's Hospital Group Board, with its own budget and management, is to be set up to progress the development of the new National Paediatric Hospital.
Minister for Health Minister James Reilly said the three children's hospitals have agreed to become a single service before the new hospital is built.
He was speaking at a national health summit in Dublin.
The existing National Paediatric Hospital Board will be restructured to focus on the capital project and new legislation will be required for this change.
Mr Reilly also said he will shortly bring to Government a report on Hospital Groups and a Smaller Hospital Framework.
He promised that no acute hospital will close.