A leading doctor has described St James's Hospital in Dublin as "the worst possible location" for the National Children's Hospital.
Dr James Sheehan, one of the founders of the Blackrock Clinic, says there are a litany of problems with the site in Kilmainham.
He says the hospital should be built on a greenfield site close to Blanchardstown Hospital, which he says is already owned by the State.
He is appealing to the Government to reconsider its plans for the St James's site.
Dr Sheehan said: "The children's hospital would need to go up to nine floors in a two-storey area.
"The traffic is chaotic already in that area, there's totally inadequate parking.
"The main Dublin sewer, the Drimnagh sewer runs from north to south of that very site, and you all know what happens with sewers, they attract rats."