The disclosure comes as Labour denied that an intervention from Tánaiste Eamon Gilmore had caused a further delay in the process.
Former Dublin City manager John Fitzgerald has been asked to assess potential locations for their suitability in terms of planning.
A Government source said ministers wanted to avoid a repetition of what he called the debacle of the Mater site being chosen and then rejected after being refused planning permission.
Mr Fitzgerald, a respected official who headed up the Limerick regeneration project, was approached recently.
His review is the latest in a series of attempts to bring the long-running process to a conclusion.