THE Minister for Health has "sincerely" apologised over an answer he gave to the Dail about the overspend at the National Children's Hospital project.
Simon Harris apologised for information he gave about the costs, admitting he should have answered it "more fully".
He told the Dail on Tuesday he was not in a position to give commercially sensitive figures at the time.
"It has never been my intention to mislead the Dail," he said.
"I should have added further detail to inform that a process was ongoing to find out the cost and that updated costs would be known when that process concluded.
"I sincerely apologise for not doing this and I specifically apologise to Mr [Barry] Cowen who tabled the question.
"I have always tried to approach my work in this house, especially as health minister, in a collaborative way."
The estimated cost of the new hospital, on the campus of St James's Hospital in Dublin, has risen from an original estimate of €650m to more than €1.7bn.
The minister said an inquiry set up to assess the overruns will provide a report by the end of next month.
Mr Harris added: "It will not be found wanting when it comes to acting against any entity or any company if errors were made.
"Lessons must and will be learned and cabinet took a number of decisions in that regard today."
Taoiseach Leo Varadkar said that he understands tax payers have been left "annoyed" that costs of the project have escalated.
"It is a case of government and our agents underestimating the cost of this project and we have to accept responsibility and be accountable for that," he added.
Leader of the opposition party Micheal Martin said it was a "remarkable increase" of costs.
Speaking during leaders' questions, he said: "Are we to seriously believe the secretary generals of finance and health had no discussions about this between August and November last year or indeed that the two ministers didn't.
"Because if that is the case then that raises fundamental issues in terms of the governance and competence and management of the budgetary process itself.
"Was it a case this project was too big and politically you invested too much and it was too late to stop and too late to relocate, but it seems there was an extraordinary silence across government on this over a long period of time."
Sinn Fein president Mary Lou McDonald said: "It is extraordinary to hear you again, taoiseach, try to justify or to explain away this fiasco as if to suggest to the taxpayer it's actually not such a big deal after all.
"What is most extraordinary is to hear your collation partner Micheal Martin extol the extraordinariness of the situation and then resolve to back you and back your incompetent minister for health Simon Harris.
"It is crystal clear at this juncture that the minister for health is incapable of solving it, in fact he is part of the problem.
"Fianna Fail might be prepared to sit on their hands, we won't."
Independent TD Michael Lowry said: "The perception out there amongst the working people is they are questioning the misuse of public monies.
"At a time when many Irish households struggle with every day costs like childcare, mortgages, rent and insurance there is a strongly held sentiment on the ground that public monies are being squandered with unnecessary layers of bureaucracy."
