Health Minister James Reilly has said that there was an environmental study carried out on the proposed plans for a new children's hospital at the Mater in Dublin.
At an oral hearing on the plan today An Bord Pleanala was told that the Department of Health failed to comply with an EU requirement for a strategic environmental assessment of the hospital.
And it heard that this may be a "fatal legal flaw".
But Minister Reilly said that as far as he is concerned, that is not the case.
"My understanding is that there was quite a substantial environmental statement made at the very outset of this process," Minister Reilly said.