Figures show as many as 200 reviews of tests suggested women should have received 'earlier intervention'
The Health Minister Simon Harris says he currently cannot have confidence in the managers of the Cervical Check screening programme.
It comes amid revelations that more than 200 reviews of tests suggested women with cervical cancer should have received 'earlier intervention'.
According to The Irish Times, that number is almost half of the 442 cervical cancer cases where a review was warranted.
Taoiseach Leo Varadkar has said he thinks most of the affected patients have since been informed, adding that they are investigating that and have written to doctors.
"In terms of individual personnel, like I say, the minister has initiated a review - I don't want to be condemning any individual at this stage without knowing the facts.
"But we are going to make sure we establish the facts of this affair - and we want to make sure as well, as a Government, that something good comes of this".
Minister Harris was asked by reporters earlier if he has confidence in the managers of Cervical Check.
He responded: "I have full confidence in the screening programme. I think that's important to say.
"It's so important that people use the screening programme: it saves lives, it has detected cancers, and it has helped reduce the rate of cervical cancer.
"Truthfully, in answer to your question, I can't say that I do currently... and that's why I have ordered a review."
The clinical director of the Cervical Check, Grainne Flannely, was asked for her response to the health minister's criticism.
She said: "What he did say is he has confidence in the cervical screening programme, and recommended that women still take part in the screening programme.
"Obviously he has considered a peer review of our programme - we would welcome that.
"We think our programme, on a peer review, will stand up with any other programme in the world".
The latest figures were released after Vicky Phelan's case this week highlighted the issue.
She settled a case against a US lab on Wednesday, after being wrongly informed in 2011 that she had the all clear.
Three years later, a review found the results were incorrect.
She was diagnosed with cervical cancer around the same time, but she only found out about that review last year.
A full review of the screening system has now been ordered, and questions are being asked as to why tests are being outsourced to US labs.
Junior Minister Catherine Byrne says all elements of the CervicalCheck programme need to be looked at.
She said: "The numbers speak for themselves. Only one is too many. 200, or whatever the number out there is, is too many."
Speaking about concerns about moving testing away from Ireland, Catherine Byrne observed: "Yes, [those fears] may have been justified [...] That's what this review should be about as well... where these smear tests go to be examined.
"Women's lives are at risk here. No woman or young girl should have to face an uncertain future because of a test being misdiagnosed."
She added: "We have to get to the bottom of why these numbers are so high."
The Junior Minister acknowledged that 'communication failed' in the Vicky Phelan case.
She said: "It's obvious from listening to Ms Phelan, and listening to the Tánaiste and Minister Harris that communication on her diagnosis failed.
"Where along the line or chain that happened I don't really know - but however, it has happened, and it has to be rectified."
Announcing the CervicalCheck review yesterday, Minister Harris said the scheme needs to be reviewed.
He said: "We need people to have absolute confidence in our screening programmes - and I have confidence in it: it is a progamme that saves lives.
"But it is a progamme that's 10-years-old this year and I think therefore it is appropriate that we would review it."
In a statement yesterday, the HSE said: "Up to recently, the outcomes of this review have been sent to a woman’s treating doctor, with advice to use their clinical judgment to communicate this to the woman.
"While the HSE is confident that the majority of women involved in this process have already been contacted by their doctor, Cervicalcheck is today writing to those doctors who were originally requested to contact patients confirm that this has occurred. We are seeking to ensure that this will take place in an expedient manner."
The statement adds that the HSE will soon be moving to an "even more effective means of screening".
Reporting by Sean Defoe, Stephen McNeice and Jack Quann