The Department of Health's insisting Mary Harney only became aware of the scale of the x-ray problem at Tallaght hospital in Dublin yesterday.
58,000 x-rays at the hospital were never examined by a consultant radiologist between 2005 and September last year.
One person's already died, while another's seriously ill as a result of a delayed diagnosis.
The Chief Executive of the Hospital says he brought the matter to the attention of the Health Minister on December 15th.
But Junior Minister Barry Andrews has told the Dáil Mary Harney only became aware of the extent of the issue yesterday:
Meanwhile, Donegal North East TD Jim McDaid says he believes this is "media overkill" and the clinicians who read the x-rays should be given great credit for only missing two cases.