Schools are set to remain closed and non-essential construction is to stop under new plans agreed by the Cabinet.
It was widely expected that schools would remain shut for at least the month of January.
It has been agreed that schools won't reopen for most students this month but Leaving Cert students will be allowed to attend school three days per week, while special education will remain open.
All other teaching will move online.
Taoiseach Micheál Martin said they will do everything they can to ensure Leaving Cert students will be able to sit exams normally this year.
Education Minister Normal Foley said that schools remained safe places during the last term.
"Our schools...are confirmed to be safe places," she said, adding that the closure of schools was happening to minimise the movement of people in society.
Meanwhile, construction projects will stop, but essential projects will be exempt.
Speaking at a press conference this afternoon Taoiseach Micheál Martin said that hospitals were "under siege" from the Covid-19 virus.
"We must face the coming month with steely determination and resolve," he said.
Tánaiste Leo Varadkar said the positivity rate for Covid-19 is at around 25%.
"We are facing into what is going to be a very dark January," he said, adding that the virus spread needs to be slowed by staying at home.
He announced that the PUP would remain in place as is until at least March 31, as will the EWSS and weekly payment to closed businesses.
Transport Minister Eamon Ryan explained that all passengers from UK must provide proof of a negative PCR test for Covid-19 within 72 hours before travel to Ireland from this weekend. Failure to do so will result in a fine or up to six months in prison.
The plans are expected to be broadened to other jurisdictions in the coming weeks.
Schools will remain closed until 1st February. Exceptions are in place, including a provision for all 6th year Leaving Certificate students to attend school for 3 days a week commencing the week of 11th January, and certain provisions for special education and specialised settings. See notes below for complete list of exceptions.
The resumption of the ECCE programme is delayed until 1st February.
Childcare services, including regulated childminders, will remain closed with the exception of services for vulnerable children and children of essential workers. Other existing childcare arrangements can continue to operate for vulnerable children and children of essential workers only. In addition, a household of an essential worker, without an existing childcare arrangement, can form a bubble with another household for the purpose of providing childcare.
Construction will be closed with effect from 6pm on Friday 8th January, with limited exceptions for essential cases.
Click and collect from non-essential retail outlets should no longer be permitted with immediate effect. (Existing orders may be collected). Click and deliver will continue to be permitted.
The Government also agreed that the current travel moratorium in place for travel from Great Britain and South Africa is extended until midnight Friday 8th January 2021. From 9th January 2021, all passengers arriving at Irish airports and ports whose journey originates in Great Britain or South Africa will be requested to have evidence of a negative result from a PCR Covid-19 test taken up to 72 hours prior to arrival in Ireland.
This new mandatory requirement will be in place until 31st January 2021, and will be kept under review in light of the evolving epidemiological situation.