Nursing home residents will be able to see more visitors and go on organised outings as restrictions are eased.
Where around eight out of every 10 residents have been vaccinated, residents will be allowed have four visits, by two people each week.
Organised outings for residents by bus or car will also be possible, once there is a high level of vaccination among residents and if a risk assessment has been conducted in each case.
Nursing Homes Ireland CEO Tadhg Daly said it is a hugely important day.
Speaking on RTÉ's Today with Claire Byrne, he said there may be some local variations in terms of the new guidelines, if for example there is an outbreak in the area or a high level of community transmission.
He said visitors should contact the nursing home beforehand as it will be challenging with large numbers of footfall.
Sage Advocacy Executive Director Sarah Lennon said the new guidelines marked a vitally important step towards a more normal daily life for the country's estimated 32,000 nursing home residents and their families.
She said a survey by Sage Advocacy showed that some families with relatives in some nursing homes are unhappy with the approach taken by some home providers to facilitating visits.
The CEO of the Alzheimer Society of Ireland also welcomed the changes and described it as a major step forward.
Speaking on RTÉ's Morning Ireland, Pat McLoughlin said the lack of face-to-face visits over the last 13 months has resulted in lack of stimulation and socialisation for residents, with carers reporting that residents have become more isolated and withdrawn.
He said it is only when the visits stop that people realise how much stimulation family and friends were providing.
In addition, nursing home staff could also rely on visitors to tell them if there were any areas of concern, he said.