Schools will not reopen on Monday as previously planned and will remain shut until the end of January.
Leaving Cert students will be asked to attend three days a week, with exceptions also in place for children with special needs.
Leaving Cert students should continue to attend for three days a week from Jan 11, and special schools/classes continue - but otherwise mainstream schooling is closed for January. The Taoiseach acknowledges that this is a new level of disruption
— Gavan Reilly (@gavreilly) January 6, 2021
Pre-schools are also set to close with crèches only open for vulnerable children and the children of essential workers.
Meanwhile, non-essential construction sites will close at the end of the week.
The construction of social housing and other essential projects may continue.
The Taoiseach also appealed to employers to allow workers to work from home if possible.
"Unless you're involved in essential work, you’ve no reason to be away from home” - pretty simple message from Taoiseach Micheal Martin.
— Ben Finnegan (@_BenFinnegan) January 6, 2021
Non-essential shops will be instructed to end click-and-collect services and will only be permitted to operate delivery services.
On international travel, passengers coming into Ireland will soon have to present a negative coronavirus test on arrival.
Passengers will have to sit the PCR test within three days of travelling here and will still have to self-isolate for 14 days.
The new rules will come into force for travellers from Britain and South Africa on Saturday, with other countries to follow.