The Health Minister has denied that he ignored advice that facilitating repeat smears would have serious consequences on CervicalCheck.
Former Clinical Lead of the service Grainne Flannelly says she warned colleagues that the laboratories would not have the capacity to deal with an influx of tests.
Her advice was passed on to the Department of Health which decided to proceed with issuing free out-of-cycle smears for women.
Simon Harris says he was never advised of Grainne Flannelly's concerns.
He said: "I never received any contrary advice in relation to the provision of free repeat smear tests.
"It is clear that after the decision was made that some in the CervicalCheck programme did express some concerns about the operationalising of it."
Fianna Fáil's Health Spokesman Stephen Donnelly says if Minister Harris knew about it then he will have misled the Dáil a second time.
He said: "What she says directly contradicts the minister's position.
"What she said suggests that the minister has, in fact, misled the Dáil for a second time - he misled the Dáil on the children's hospital and has apologised for doing so."
The former head of CervicalCheck said she warned free smear test re-checks would 'fundamentally undermine the screening programme'.
The re-tests offered by Minister Simon Harris have led to a massive backlog, with delays of up to 33 weeks.
In a submission to the Oireachtas Health Committee, former clinical director of Cervical Grainne Flannelly says she warned against offering free repeat smear tests in the wake of last years scandal.
She told colleagues in the National Screening Service the capacity was not there to process the tests - and that there would be long delays as a result.
Prof Flannelly said she believed doing so would 'fundamentally undermine the screening process'.
Those concerns were passed on within the hour to the Department of Health which - according to Prof Flannelly - responded that it was to proceed with the policy change in any case.
Minister Simon Harris announced free repeat smear tests later that day.
However, in a parliamentary question, this year Minister Harris insisted neither he or his officials received advice against the re-tests in advance of the decision.
He said there was subsequent contact from the National Screening Service with concerns - but that they failed to recognise the circumstances of the crisis.
Minister Harris said not providing the free re-tests would have been untenable in the circumstances.