A probe is under way into why a hospital failed to report well over 200 positive cases of the coronavirus diagnosed since mid-March until yesterday - causing a big jump in newly diagnosed figures just days before Monday's easing of lockdown.
Chief medical officer Dr Tony Holohan said he was only informed yesterday of the large batch of cases from the hospital, which he did not name.
It comes as two more healthcare workers have died, bringing their death toll to seven.
Covid-19 is a notifiable disease and it is essential for accurate surveillance and detection of any worrying patterns in the spread of the virus that cases are reported as quickly as possible.
The delayed reporting from the hospital led to a total of 426 new cases being reported yesterday - much higher than in recent days.
Yesterday's cases were also driven by large outbreak of infection in a meat plant in the south of the country.
Dr Holohan said he will write to all hospitals to remind them of the necessity to promptly report cases of the virus to allow for proper surveillance.
"There is an obligation to make those notifications," he said. He did not believe deaths at the hospital from the virus were not reported and said the local occupational service would have been responsible for tracing contacts of confirmed cases.
There are now 23,827 reported cases of the infection so far. Another 10 people died from the virus, pushing the total to 1,506.
Dr Holohan said the National Public Health Emergency Team has made recommendations to the Government on the start of phase one of easing the lockdown and this will include the use of face coverings in certain circumstances.
Prof Philip Nolan of Maynooth University, chairman of the team advising on the patterns of the virus, said: "All indicators of the spread of Covid-19 are decreasing, including the average number of cases per day, number of people in hospital and ICU, admissions to ICU and number of reported deaths per day.
"This is reinforced by our estimate reproduction number which is currently stable between 0.4 and 0.6.
"We will be monitoring this figure and the overall number of infections in the population very closely over the coming weeks."
The average number of daily deaths over the past three weeks had fallen from 33 to 21, to around 13 this week.
There are now 58 patients in intensive care compared with 140 at its height, added.
Earlier yesterday HSE chief Paul Reid said it is promising a three-day turnaround for coronavirus tests and tracing from next week in all but a small number of complex cases.
It has the capacity to carry out 15,000 tests a day. People who get a negative result will be told in less than or equal to two days, he said.
For those who test positive it will take three days to begin tracing their contacts who might have been exposed to the virus.
Mr Reid said only 3pc of cases are positive so out of 12,000 cases 450 people would have the virus.
Most of those are straightforward when tracing their contacts but there are complex cases such as people without English, nursing home residents or patients in intensive care which take longer to track down.
The system is currently hampered by blockages including reliance on manual process and the problem of some computers not talking each other.
Asked about plans to reopen crèches and the collapse of the in-house childminding scheme for healthcare workers, Dr Holohan indicated that the team may consider if this should happen earlier than the planned six weeks timeline in the roadmap to exit lockdown.
He said he was very sensitive to the challenge for parents and how it was having an impact on going out to work.
"We will continue to assess the whole question ," he added, saying it would depend on the path of the infection.
He said the roadmap is "a living document" and not rigid.
Asked about reliance of childminders in the home, which is in breach of advice, he said he would not criticise people and overall there was a high level of compliance but he was aware that following advice was putting a strain on people.
Asked about correspondence from HSE chief Paul Reid showing tensions over the announcement by the National Public Health Emergency Team (Nphet) about the need to carry out 100,000 tests a week, and the failure to give the HSE notice, he said there can be "communications challenges".
The plan for 100,000 tests was discussed by the expert group at their meeting weeks ago and communicated to the HSE around the same time, he said.
Dr Colm Henry, HSE chief clinical adviser, said it would be "implausible" to think there are no tensions within Nphet or between Nphet, given the "real time, tough" decisions to be made about a new virus.
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