Minister for Health Stephen Donnelly has said he is "deeply frustrated with the ongoing delays from the contractor" of the National Children's Hospital and "with the level of claims from the contractor coming in now at nearly €760 million".
Last month, an Oireachtas committee was told that the cost of the new NCH could top €2 billion.
Stephen Donnelly said he is "absolutely determined that we are going to get children treated in this hospital as quickly as possible".
Speaking on RTÉ's Morning Ireland, he said there has been "intensive engagement" between the board and the contractor in recent months.
Mr Donnelly said the contractor had submitted a completion date of March 2024, then May 2024, then a further date which "at this point the board has not accepted and is in very intensive engagement with the contractor on this".
He said so far about €12 million in claims has been awarded, adding that it is not enough just to keep the cost down, the hospital has to be opened.
He blamed the delay on three things: the Covid-19 pandemic, the war in Ukraine, and the "very significant resources" the board received to fight the claims.
Read more: After years of debate, nobody can say when NCH open
Mr Donnelly added that the board has made it clear to the contractor that "it is not getting anything like" the €760 million in claims that it is seeking, which he said is an "ongoing intensive interaction" between them, some of which are in the courts and some in the dispute resolution mechanism set up within the contract.
He said the time spent fighting each claim "doesn't have to" knock back the completion date for the hospital.
Mr Donnelly said the hospital is "90% complete, there's 10% left, and the focus at the moment is inside the hospital, mainly on finishing out the mechanical and the electrical works".
The board is responsible for overall delivery of the hospital, while BAM is the build-only contractor and is neither the designer nor developer of the project.
In a statement following a committee hearing last month, BAM said: "BAM categorically rejects any allegations of under-performance and under-resourcing on the new children's hospital project.
"Any suggestion that BAM is deliberately not committing adequate resources to the project or is in any way slowing down delivery of the hospital is untrue."
The project has crashed through its original completion deadline of August 2022.
Social Democrats TD Catherine Murphy described Mr Donnelly's comments as "deeply troubling".
In a statement, she said: "While conceding that the latest completion date of May 2024 will not be met, he refused to reveal the revised handover deadline put forward by the developer. This suggests there has been a further drift in the works schedule that far exceeds our worst expectations."
Deputy Murphy added: "It beggars belief that the Minister is unable to provide even minimal clarity about what is the biggest capital project in the history of the health service."
