Taoiseach Leo Varadkar said he has been left "very disappointed" at the spiralling cost of building the new National Children's Hospital.
He said further investigations into the overrun of the children's hospital building will take place in the new year to ensure there are no more cost escalations.
The bill for the new building at St James's Hospital was estimated to cost around €1bn; however the price of developing the facility has now risen to almost €1.4bn, and is expected to go higher.
Some of the extra costs include construction inflation and VAT. "I am very dissatisfied with what has happened in the past year," he said.
"I have an understanding of why that is the case, some of it is VAT, some of it is construction inflation, some of it is because it is going to be 'specced' in a different way, from sprinklers to ceiling heights, so this is money that will need to be spent. But it should have been anticipated. The model to set up to build this hospital was different.
"It is not being built by the HSE or the OPW (Office of Public Works). It is not being done in the normal way.
"It is being done by a dedicated build board set up by legislation with very good people and very good staff who have experience in building big projects. So it is very disappointing that this has happened."
Mr Varadkar said he was worried about the cost of running the hospital on a day-to-day basis.
"We need to make sure the operational costs of running the hospital are benchmarked with similar hospitals internationally," he added.
The hospital is set to be one of the most expensive children's hospitals in the world.
"I can live with that if it turns out to be one of the best," Mr Varadkar added. "But I don't want to have a children's' hospital which is one of the most expensive to run."
The Fine Gael leader added that the Public Accounts Committee and Health Committee will investigate who is responsible for the overrun and look at whether anyone will be held to account.
Mr Varadkar said that action will be taken to reduce the cost of healthcare in the new year including the reduction in costs of medicines from March and the extension of GP visit cards to more people.