All of the country's hospitals are to have their Covid-19 reporting systems examined urgently after it emerged one hospital failed to report 250 confirmed cases until yesterday evening.
Some of the cases involving patients at the unnamed hospital date as far back March.
In total, there are now 23,847 confirmed Covid-19 cases here while the death toll has risen to 1,506.
We will know later if Phase One of the lifting of restrictions can take place on Monday after Cabinet ministers meet to agree on the measures.
Chief Medical Officer, Dr Tony Holohan, says hospitals are legally obliged to report cases of the virus immediately.
"I think that the majority of hospitals have taken the responsible and legally mandated action to report these cases," said Dr Holohan.
"This is all set out in the 1947 legislation the notification of infectious diseases."
Dr Holohan said that there is an expectation and an obligation in the legislation for people to make those notifications.
The delay in reporting resulted in the daily tally of confirmed Covid-19 cases announced yesterday to be significantly higher than those of recent days.
Dr Holohan stressed that the 426 cases was not evidence of a “new wave” of infection, insisting that almost 300 related to the batch of unreported test results from the one hospital.
Dr Holohan said the unreported batch, and the distribution of those cases across the last two months, did not give cause to alter any existing conclusions about the virus’s spread in the country as a whole.
But he added: “That’s not me saying that this is okay.
“We want to encourage appropriate reporting and timely reporting and comprehensive reporting, a high standard of collection of all the key information in respect of all the cases and to have that reported to us in as timely a way as possible.”
The CMO said it was not the time to talk about “consequences” for those responsible for the delayed reporting, insisting it was more important to establish the facts and make sure it would not happen again.
He said he could not be certain the required contact tracing had been carried out for the cases who had tested positive in the hospital, but he expressed hope it would have been done.
“I would like to think the contact tracing necessary in the hospital environment by the occupational health teams might have been carried out but I don’t know that as a fact,” he said.
Additional reporting by Press Association