Health Minister Simon Harris has blamed design elements for the spiralling costs of the national children's hospital and pledged to use the “full rigour of the law” to pursue those responsible for the huge bill.
An “early warning” system for the project had been lacking, admitted Mr Harris.
But he also stood over the €1.4bn build, describing it as “a reasonable price” for the children's hospital.
Pressure is now mounting to explain why the minister and health officials, who were on boards overseeing the project, did not raise alarm bells over the spend ahead of last year's Budget.
A price of €983m was agreed for the hospital in April 2017.
By August 2017, initial overruns of €61m were flagged.
Mr Harris said he was told of these by that September.
He told the Oireachtas Health Committee that the National Paediatric Development Board (NPDB) was at that stage told to mitigate costs, through savings in engineering or design.
He then explained more about what the department secretary general, Jim Breslin, told him at the time in late 2017: “Yes, there is a cost pressure here.
The next time Mr Harris said cost concerns were flagged with him was a year later, on August 27, 2018.
It emerged yesterday that several Department of Health and HSE officials at committee meetings repeatedly discussed cost concerns during that year, up until the summer of 2018.
Mr Breslin said he came back after the summer in 2018, “surprised” at the inflated pricing for the project.
He and the minister were aware that potentially the final cost for the hospital could be hundreds of millions of euro more.
But they both told the committee that there were no specifics at the time.
HSE deputy director general Dean Sullivan admitted that earlier that year, concerns had been raised about the cost.
Mr Sullivan who sits on a steering group for the project, said “there was noise in the system in April...there could have been another €50m coming over the hill.”
Fine Gael TD Kate O'Connell lashed the HSE official for using such fickle language about public funds.
It was “not normal” for taxpayers' money to be described as noise, she said.
She said it was "not credible" that not one health official had raised a flag about the overrun with the government during those months.
Officials were “taking us for fools,” she argued.
Even a high-level official in the Department of Public Expenditure - a “man in charge of shopping” for the nation Ms O'Connell said - had not told ministers about the costs, despite sitting on one of the three boards overseeing the project.
TDs queried the awarding of the contract to Dutch construction firm BAM, whose bid was €130m lower than the next.
Sinn Féin's Louise O'Reilly said it was an “abnormally low tender price”.
Mr Harris, said that, when looking at the quantities between the detailed design and the outlay, somebody did get it “seriously wrong”.
But he also said that €1.4bn was a "reasonable price" for the hospital.