The entire country is to be moved to level 3 of the Government's COVID-19 plan, with an emphasis on improved enforcement of restrictions.
NPHET had recommended that the entire country be placed on level 5, which is the strictest level available. However, this was rejected by Cabinet, which met in an emergency meeting on Monday to discuss the issue.
Earlier on Monday, the three coalition party leaders, Micheál Martin, Leo Varadkar and Eamon Ryan, had met with the chief medical officer, Dr Tony Holohan, for over two hours.
Announcing the restrictions on Monday night, the Taoiseach, Micheál Martin, said that "the facts show that there has been an exponential growth" in cases. He said that the country must respond, but the challenge is for this response "to be effective and proportionate".
The new restrictions will come into force nationwide at midnight on Tuesday night, for a period of three weeks.
"The virus has challenged us to our very core, but if we all act now, we can stop the need to go further, to level 4 or 5...The most important thing to remember is that what happens next is in our hands," the Taoiseach added.
The news comes after a further 518 cases of the virus were confirmed, bringing the total number of cases here to 38,549. No new deaths were reported, leaving the total number of deaths at 1,810.
Of the 518 new cases, 134 occurred in Dublin, 53 in Cork, 49 in Limerick, 34 in Donegal, 32 in Meath and the remaining 216 cases were spread across 20 counties.
Speaking earlier about the figures, Dr Holohan said that in recent days, "we have seen a significant and concerning deterioration in the epidemiological situation nationally".
"It is vital that we do everything in our power now to arrest the current trajectory nationally and very substantially suppress the virus back down to a low level of transmission in advance of the winter months," he said.
He urged people not to become distracted away from the core public health measures of washing hands regularly, socially distancing, wearing face masks where appropriate, avoiding crowded environments, and cutting social contacts down "to minimum levels".
If people have symptoms, they should self-isolate immediately and call their GP.
"Our core priorities have to be protected. We must work together to keep our non-COVID health services open, keep our children in education and protect the lives of the most vulnerable to this disease.
"Solidarity is now more important than ever as we work to once again suppress this virus in our communities," added the deputy chief medical officer, Dr Ronan Glynn.
For more on what is and is not allowed at level 3, click here.
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