Construction safety risks caused by the lack of space at the site of the troubled new National Children's Hospital are a "concern", the Oireachtas health committee has been told.
The warning came as the new chairman of the board overseeing the project gave his first briefing to the committee.
Fred Barry cast doubt on any scope for cutting the existing massive cost of the project, which has spiralled to €1.4bn.
He also revealed that he is as concerned about safety at the St James's Hospital site as efficiency.
However, he ruled out moving it to another location, although the size of the site poses definite constraints and there is no significant space for stacking building supplies.
Mr Barry, a chartered engineer and former National Roads Authority chief, was appointed after the previous chairman Tom Costello stepped down amid public furore over the soaring cost of the hospital.
"Our challenge over the next few years is getting it built," said Mr Barry.
"It is a very constrained site and the challenge is to get it built safely and not have accidents on the site."
He also confirmed that the building firm BAM will continue to hold the construction contract.
If the work was re-tendered it could lead to a two-year setback as well as payouts to BAM, he said.
Mr Barry indicated that the escalation in the hospital bill - which saw it rise €450m since April 2017 - may have been due to an early underestimation of cost rather than an overrun.
Responding to questions from the Fianna Fail spokesman on health, Deputy Stephen Donnelly, he cautioned that the big challenge will be trying to stop the cost increasing in the future.
BAM is entitled to make additional claims if construction inflation goes over 4pc in any year before it is built in 2022.
Construction inflation is difficult to predict and it will depend on how heated the economy is, Mr Barry added.
If there are further design changes proposed the board will have to assess if they are worth the extra cost.
He pledged that if there are signs of escalating costs in the future, the board will flag them early on.
"I worked as chief executive of the National Roads Authority at a time when we built much of the motorway network," he told the committee.
"The new children's hospital is not just another big infrastructure project. It will be transformational for the care we give our children and young people, who represent about a quarter of our population.
"I am honoured to be asked to play a role in its development and finally I look forward to working with you on this great national project."