The Government will take "decisive and nationwide" action on Monday over the rising number of coronavirus cases, a minister has said.
It comes after political leaders received briefings from health officials in Dublin on Saturday about their concerns at the recent rapid spread of the virus.
Minister Simon Harris said: "The Government will act tomorrow, the action will be decisive and the action will be right across the country, it'll be nationwide action.
"It's clear now that the virus is at such a level within all our communities, the county-by-county approach will not be sufficient.
"So tomorrow we will have to bring in more restrictions.
"Level 3 has not worked in terms of getting the virus to where it needs to get to."
But, what are the differences between Level 4 and Level 5 guidelines?
At Level 4, the priority is to keep schools and childcare services open, while keeping people safe. No visitors to private homes or social gatherings are allowed while only businesses and services deemed to be essential will be open.
At Level 5, the public health risk means that people will be asked to stay at home, except to exercise within five kilometres of their home. There will be no gatherings other than small numbers at funerals and weddings.
At Level 4 can be attended by up to 25 mourners while at Level 5 they can be attended by up to 10 mourners.
At Level 4 such as outdoor arts events and training events with a named organiser, owner or manager can take place with up to 15 people. At Level 5 they should no longer take place.
At both Levels 4 and 5 do not permit any visitors. No social or family gatherings should take place in other settings also.
At both Levels 4 and 5 ceremonies and receptions can be attended by up to 6 guests. Guests cannot leave their county to attend a wedding under Level 4. It is unclear if they can travel beyond five kilometres to attend a wedding under Level 5.
At both Levels 4 and 5 must move online with places of worship remaining open for private prayer.
At both Levels 4 and 5 such as events in theatres, cinemas, arts events, business events, training events or conferences should not take place.
At Level 4 are in place as people are asked to stay in their county apart from work, education and other essential purposes. At Level 5 stricter restrictions are in place as people are asked to stay at home and exercise within five kilometres of their homes.
At Level 4 will remain open with protective measures.
At Level 4 such as universities must move primarily online with appropriate protective measures in place for essential attendance on site. At Level 5 all will be subject to “recommendations based on situation and evidence at time.”
At Level 4 should take place, with only essential or other "designated" workers attending in person. At Level 5 only those working in health, social care or other essential services can attend work in person.
At both Levels 4 and 5 face coverings must be worn, capacity will be limited to 25 per cent, and the service should be used for essential workers and purposes only.
At both Levels 4 and 5 they should "exercise judgement" regarding the extent to which they engage with others and in activities outside home, with specific guidance set to be provided.
At both Levels 4 and 5 visits are suspended aside from “critical and compassionate circumstances.” Businesses and services - differences Bars, cafes, restaurants and wet pubs: At Level 4 can remain open for outdoor dining with a maximum of 15 people and takeaways only. At Level 5 they can open for takeaway or delivery only.
At Level 4 can remain open for existing guests only and for those with essential non-social and non-tourist purposes. At Level 5 they can remain open for those with essential non-social and non-tourist purposes only.
At Level 4 that are primarily outdoors only can remain open. All other retail and personal services will be closed. At Level 5 only essential retailers can remain open with the wearing of face coverings. All other retail and personal services will be closed.
At both Levels 4 and 5 they must all be closed.
At both Levels 4 and 5 they will remain closed.
At Level 4 can take place in pods of up to 15. Indoor training: At Level 4 can only be undertaken by individuals, with no exercise or dance classes. At Level 5 both indoor and outdoor training can take place for individuals only.
At Level 4 most cannot take place, with exemptions for professional, elite, inter-country and horse-racing taking place behind closed doors. At Level 5 no matches and events can take place, with no exemptions.
At both Levels 4 and 5 they will be closed.