Building the new National Children's Hospital on an alternative site to the Mater would not reduce its 650 million euro bill, an architect has said.
An independent cost comparison of the controversial Dublin city centre location against three other areas on the outskirts of the city revealed little financial difference.
John Cooper, appointed by Health Minister James Reilly, said sick children would also benefit as the Mater site could be opened in the final few months of 2016 where a new site could take an extra three years to approve.
The architect and his team compared the site adjacent to the Mater Hospital against one next to the Tallaght Hospital, an undeveloped location at Newlands Cross near the M50, and one beside James Connolly Hospital in Blanchardstown.
He said the base construction costs for all four were similar, but revealed when extras for the 16-storey Mater site were included - such as enhanced facades, extra lifts and roof gardens - the other three sites were up to 25 million euro cheaper.
The Mater's four-storey basement car park also pushed the price of the project up, with parking at the other three sites making them between 37 million euro and 57 million euro less.
Equipment, design fees and VAT were subsequently added on, pushing the other three sites between 60 million euro and 86 million euro cheaper to build on than at the Mater.
However the rise in inflation when the building would start on them in two-and-a-half years' time reduced the disparity between the Mater back to between 30 million euro and 60 million euro.
Upgrades to the road networks and utilities in Tallaght, and more importantly at the greenfield site in Newlands Cross, again cut the difference to between 26.1 million euro and 51.7 million euro.
Another issue for the team was 26 million euro in non-recoverable costs for the Mater site, which Mr Cooper said would have to be taken from the budgets of the three other sites.