Inflation and the cost of cables and fire sprinklers are being partly blamed for the huge cost overruns in building the National Children’s Hospital.

It emerged last month that the 470-bed hospital, which will be located on the St James's Hospital campus in Dublin, will now cost at least €1.4 billion - more than double the original price tag.

The National Paediatric Hospital Development Board is responsible for overseeing the project, and says the new facility be the finest in the world.

However, its members have today found themselves defending the costly project as they appear in front of the Oireachtas Health Committee.

Fianna Fáil’s Stephen Donnelly has accused the board of a "complete and catastrophic failure", and predicted the final budget could expand to almost €2 billion.

John Pollock, project director, was asked by Deputy Donnelly if any new beds would be part of the spending increase.

He answered: "It has the same number of beds as we had... there's no extra beds."

Construction costs have increased by €320 million, including new fire prevention measures after the Grenfell Tower fire and 5,500 kilometres of cable to make the hospital fully digital.

Tom Costello, chair of the board, says they would take the same approach if they were starting the project again, and insisted the "process actually worked well".

He observed: "We would adopt the same procurement approach. Notwithstanding this, we're deeply disappointed and acknowledge the very significant increases and the challenges these pose.

"What's very disappointing is that at the tender stage, the price that ultimately fed into the contract award underestimated what the real cost of doing the job is."