A food factory in Co Kildare has suspended all processing operations as a precautionary measure following confirmation of 80 Covid-19 cases.
O'Brien Fine Foods in Timahoe said they took the decision to test all of its employees following a confirmed case of the virus on 30 July. The company said this was their third case at the facility at that point.
In a statement, the food company said it engaged with the Health Service Executive and a private testing provider to "expediate" testing.
"Of 243 tests completed, 80 have been confirmed as positive for Covid-19. Of the 80 confirmed, the level of asymptomatic infectivity appears to be very high."
Testing of a further 42 employees was being completed.
The company said that those who have tested positive have been advised to isolate and full risk assessment and contact tracing procedures are under way.
"All close contacts of those affected are being notified, advised to self-isolate and to contact their GP," it added in a statement.
The company said it has operated with "an abundance of caution and safety" since Ireland's first Covid-19 cases emerged.
It said that given its level of rigour and its comparatively low level of confirmed cases up to this point, this sudden spike is difficult to comprehend.
Meanwhile, a specific warning has been issued for people living in Kildare, Laois and Offaly, which saw 226 cases over the past 14 days.
Acting Chief Medical Officer Dr Ronan Glynn has said everyone in those three counties needs to pay particular attention if they have any symptoms of Covid-19 and double down on public health measures.
At a Department of Health briefing tonight, Dr Glynn said there had been "four significant outbreaks in meat processing type facilities" across counties Kildare and Offaly.
The Acting Chief Medical Officer said two of the outbreaks have been in a dog food factory in Naas in Co Kildare and at a meat processing plant in Tullamore, Co Offaly.
Dr Glynn said the other two are in meat processing factories in Kildare town and in Timahoe in Co Kildare.
He said the locations of the factories are one thing, but he said clearly the people working in the factories live in a range of places within these counties.
Dr Glynn said there should not be an undue focus on particular locations, as he said "the counties as a whole need to be careful".
To date, he said, there have been around 150 cases in three of those sites.
There have also been a number of clusters in three direct provision centres in the Midlands, which Dr Glynn said now appear to be under control.
He said that the National Public Health Emergency Team (NPHET) has recommended this week that regular testing of people living in direct provision centres is offered, beginning over the next week or two, but it will not be mandatory testing.
Unions representing workers from meat factories in the Midlands where clusters of the coronavirus have been detected have said all factories must be shut down when cases are confirmed and the workers sent home on full pay.
SIPTU area organiser Greg Ennis said that more than 9% of the workforce in the meat industry had been diagnosed with Covid-19. He said the situation was extremely serious.
He said union representatives will meet Meat Industry Ireland on Monday next to discuss what he said was a crisis situation.
In recent weeks, he said, many factories where the virus was detected did not close down while testing was continuing.
He said it was essential that workers' safety be put first and that they were allowed to return home but without pay and conditions being affected.