The restrictions put in place in Kildare, Laois and Offaly could apply to other regions in the future, the Irish health director said.
Residents are not allowed outside of those counties except under limited circumstances.
The restrictions, announced on Friday in response to the spike in the cases of Covid-19, come into effect at midnight.
Cafes, restaurants and bars are closed and there will be no sporting events.
Movie theaters and gyms were also closed under restrictions, which would remain for two weeks.
Dr Ronan Glynn told RTÉ: “The other regions won’t have much of a problem either.
“We need everyone to be vigilant and follow public health guidelines.”
On Saturday, the Irish Ministry of Health announced one more coronavirus-related deaths and 174 new cases, 110 of them in County Kildare.
Dr. Glynn said the National Public Health Emergency Team was expecting an increase in cases.
“During this week, we examined all workers at the facilities where the Covid-19 outbreak occurred, as well as those in close contact with those who had received a Covid positive result,” he said. .
“Our priority now, and our reason to propose proactive measures, is to avoid these cases and clusters leading to widespread transmission of the disease in the community.”
Under the restrictions, residents will be allowed to travel outside of the three counties for the following reasons:
- Move to and from work where it is not possible to work from home
- Attend medical appointments and pick up medications and other health products
- For important family reasons such as taking care of children, the elderly or the vulnerable – but does not include social visits
- For farming purposes including food production and animal care.
People are being asked not to come to these counties unless they work.
Visit to nursing homes, prisons and acute facilities in these three counties should be suspended, except for compassionate reasons.
Checkpoints have been set up by Gardaí (Irish police) in areas near the borders of the counties to ensure public compliance with the restrictions.
Sites of worship may remain open for private prayer, but the government is encouraging the provision of online masses and religious services. A maximum of 25 people can attend the funeral.
No sporting event or match will take place, however, non-contact and practice sports can continue outdoors for up to 15 people.
All indoor gatherings including any kind of household, private family or social gatherings in people’s homes will be restricted to up to six people from no more than three total households family.
In a televised speech on Friday night, Taoiseach (Irish Prime Minister) Micheál Martin said that the clusters are a “serious concern” and “we must protect public health”, adding that “Everything else is secondary”.
He said while the government will do everything it can to prevent a return of high-level transmission, citizens have “equal responsibility”.
“Take a break and reflect on what you can do to help businesses comply with advice and stay away from businesses that don’t follow it,” he said.
He urged everyone to live up to the words of late SDLP leader John Hume, who said “unity is power”.
- The pub is closed in the Republic of Ireland
- Face masks are recommended in high schools in Ireland
A large number of Kildare cases have been linked to outbreaks in meat and food processing plants.
A Kildare agency, O’Brien Fine Foods, of Timahoe, confirmed that they suspended operations after 80 of its employees tested positive for Covid-19.
In a statement, the food company said it had hired a private testing provider and added “the level of asymptomatic infection appears to be very high”.
Earlier this week, Professor Philip Nolan from the National Public Health Emergency Group confirmed that the Republic of Ireland’s R rate is now estimated to be 1.8.
Ratio R, or fertility rate, refers to the average number of people that a newly infected person is expected to transmit the virus to after an infection.
Professor Nolan says the number of childbirths close to two is a “serious concern”.
He added that “while we have not seen a significant increase in transmission in the community, there is a significant risk that this could develop in the coming days and weeks”.