Health Service Executive (HSE) chief Prof Brendan Drumm was accused in the Dáil yesterday of "crossing the line" and getting involved in politics.
During a debate on the Health Bill, Gay Mitchell (FG, Dublin South Central) also called for an international review of the decision to locate the proposed national children's hospital at a Mater hospital site "in the interests of transparency".
Criticising Minister for Health Mary Harney, he said she should explain the controversial decision to build at the Mater site.
"That is what she is elected, appointed and paid to do, not to put a doctor forward to explain it. No paediatrician was involved in the decision to locate this hospital. It is an extraordinary lapse."
He said: "I am sure Dr Drumm is a very good paediatrician, and I hope he is a good chief executive, but he is not a politician."
Mr Mitchell, who would prefer the hospital to be built next to St James's Hospital or the Coombe in his own constituency, said "people who have not been elected to this House should not involve themselves in politics or act as a mouthpiece for the Minister.
"I suspect, and I say this with some sadness, that the reason some people do not want an independent review is that if it is found the Mater hospital is not the right location their position will become untenable because they have put themselves out on a limb and that is not the right place for public servants to be."
He was prepared to accept the move from the Crumlin site in the interests of children. "However, I do not accept that I should be patted on the head by a task force and a chief executive of a HSE who have made the decision because they believe they know best."
Mr Mitchell said "it may be a coincidence that the Taoiseach is a former employee of the Mater hospital. It may be a coincidence that, as one doctor stated, he is invited to unveil every pane of glass that is put in. It may be a coincidence that the hospital is in the Taoiseach's constituency.
"Perhaps I am being unfair to him in raising this," he said, adding that in the interest of his electorate it was fair to raise it.
The FG MEP also criticised The Irish Timesand an editorial which, he said, stated that "the decision had been made and we should proceed with it".
Mr Mitchell believed "investigative journalism in this country has gone to sleep with regard to this decision-making process".
