Minister for Health Leo Varadkar said he was "confident, but not complacent" in relation to the plans for a new national paediatric hospital at the St James's Hospital campus which were lodged with An Bord Pleanála on Monday afternoon.
The €650 million development will result in the merger of the State's three current children hospitals - Our Lady's Children's Hospital, Crumlin, Children's University Hospital Temple Street and the National Children's Hospital.
If the application is successful building work would begin next year with the facility fully operational by 2020.
The plans also include the building of a paediatric outpatient department and care satellite centres at the existing Tallaght hospital and Connolly Hospital (Blanchardstown) sites.
The project is running years late, after an earlier plan to build the hospital at the Mater Hospital was rejected by An Bord Pleanála.
The Dáil Public Accounts Committee last year heard that about €35 million in State funding which was spent on the development of the originally hospital has been written off.
Project director of the National Paediatric Hospital Development Board, John Pollock, confirmed about €6 million to €7 million had been spent on the plan for the St James’s site last year, with a further €10 million spent this year to date.
Speaking on the site on Monday, Mr Varadkar said the planning application had now been lodged with An Bord Pleanála, which acted in a quasi-judicial way and would make the final decision as to whether the project went ahead.
If it was approved, construction could be under way within six months.
“If it doesn’t go ahead well, then yes, some money will be lost and of course any delays add cost as well because of construction inflation. Any delay can add to the cost, so I hope they’ll make a decision expeditiously.”
Asked if a ‘plan B’ had been put in place in the event the project did not get approval, Mr Varadkar said: “No, it hasn’t. All the effort and all the work has gone in to this plan and it’s a really important day today, the fact that after years of work the planning application is now lodged and subject to the approval of An Bord Pleanála we can be on site, under construction as early as February or March next year and have the satellite centres in Blanchardstown and Tallaght open in 2017 and this new hospital on this site open in 2019.
“So after decades now of debate and controversy around this, we are on the verge now, just one more step, one more hurdle to get over and we can finally get things underway.”
Asked if he was confident the plan would get the go ahead, he added: “Very confident but of course I do want to respect the role of An Bord Pleanála and they are a very professional body. They judge applications like this all the time and I am confident that they will take everything into account and make a decision.”
The site at St James’s is some 12 acres in area, three times the size of the site that had been earmarked at the Mater.
Mr Varadkar said the application marked an “important milestone” on the road to building a “world-class” new facility.
"It will be the largest single investment in healthcare in Ireland ever and subject to planning permission work will be well underway in the new year," he said.
The application comes after considerable engagement with staff from the existing children’s hospitals, families, young people and children who are or have used the service and residents from the Dublin 8 area.
Eilísh Hardiman, chief executive of the Children’s Hospital Group, said the application represented “another step on the road to bringing services in the three children’s hospitals together under one roof for the first time.”
Architectural drawings and models, as well as the full site plans and environmental impact assessment were on display at the hospital project office on Monday. An Bord Pleanála confirmed it had received material in relation to the project but had yet to verify it.