A professor says a systems breakdown is likely to blame after it was revealed that one hospital failed to report hundreds of COVID-19 cases.
The unnamed hospital in the south of the country reported around 250 cases - some of which go back as far as March - on Thursday.
It meant that the figures built up without the National Public Health Emergency (NPHET) being aware of them.
By law, infectious diseases should be notified to authorities immediately.
Chief Medical Officer Dr Tony Holohan said on Thursday: “That was something that we couldn’t have known about from where we sit and they were all reported in one day."
“The point I am making is, I know nobody here is interpreting them as being part of a new wave of infection, but to really emphasise the point, these are for the most part cases spread over a very lengthy period of time that goes back to mid-March.”
All of the country's hospitals will now have their COVID-19 systems examined to ensure they are meeting their legal obligation to report infectious diseases immediately.
It is believed contact tracing was carried out on a local level.
But Professor Paul Moynagh, head of the Department of Biology at NUI Maynooth, told Newstalk Breakfast clarity is needed as soon as possible.
"It's probably worrying in a sense that there was a systems breakdown there.
"In terms of clinical management - so in the hospitals, patients and healthcare workers - are tested, and that's really important for clinical management so I'd imagine that would have definitely applied in this case.
"But... the aspect which is probably more of concern is in terms of if the contacts were actually traced.
"So that's really, really important.
"If you look at a situation where somebody has the potential maybe to infect two or three other people, over a number of 200 to 250, then you get into quite significant numbers.
"So I think it'd be really important to check and to get clarification in terms of if those cases were actually contact traced".
"And then more widely in terms of the IT systems, it would be really important in terms of getting the explanation as to what went wrong - and to make sure that there wasn't more widespread and that it was only limited to one hospital".
