Social Democrats co-leader Roisin Shortall has said that she believes the cost of building the National Children's Hospital will eventually reach €2bn.
It comes after the board overseeing the National Children's Hospital project said that construction inflation levels are running higher than what is in the contract.
The board has said it is now working within budget since the Government approved the final bill for it last December, but it could increase the cost by up to €150m.
Ms Shortall today told RTE radio’s Morning Ireland that efforts to control the cost and should have applied from the beginning and every effort must now be made to ensure the price does not “balloon” any further.
The project has run out of control, as have many other plans including the National Broadband Plan, she warned, before adding that important projects will have to be sacrificed as a result of the failure to contain these costs.
Deputy Shortall said: "This thing has just run out of control. As indeed have many other projects, including the National Broadband Plan.
"So not only do we have a serious problem with taxpayers not getting value for money but there are opportunity costs involved here. And we're yet to hear of those important projects that will be sacrificed as a result of the failure to contain these costs."
Public health systems across Europe are based on the principles of fairness and equality, but in Ireland “we have a deeply unfair two-tier system," she said.
It did not make any sense that a publicly-funded hospital like the National Children’s Hospital would be incentivised to take in increased numbers of private patients, which would be at the expense of public patients, she said.
She said: "This new project should be underpinned by solid principles of fairness and equality."
Later, on RTE’s Today with Sean O’Rourke show Construction Industry Federation (CIF) boss Tom Parlon said that issues such as labour, availability of material and an increase in the cost of materials would have led to an increase in the cost of the project.
He pointed out that new fire safety regulations would also have increased costs.
