Fine Gael TD Alan Shatter has claimed in the Dáil that the Minister for Health is unfit for office and her word cannot be relied upon.
Mr Shatter said Mary Harney prevaricated on the issue of the development of a Cystic Fibrosis unit for St Vincent's University Hospital in Dublin.
The issue was the subject of this week's Fine Gael Private Members' motion.
Mr Shatter criticised Ms Harney for the delay in granting final approval for the project. The unit is due to be fully operational in 2011.
Under a new funding proposal, the builder will be paid at the end of construction.
The hospital said it had already secured planning permission.
Fine Gael health spokesman James Reilly said it was unacceptable that the project is not due to commence for nine months.
The Minister for Health told the Dáil it had never been the case that the project would not go ahead.
Minister Harney said the delays were due to design problems.