The Deputy Chief Medical Officer Dr Ronan Glynn is urging the unvaccinated to socialise outdoors as much as they can in the coming weeks.
The health expert issued a fresh warning to people who have yet to receive their jab as the Delta variant begins to spread across the country.
Ireland is seeing a fresh wave of cases as the more transmissible variant spreads.
On Saturday a further 1,377 cases were confirmed here.
Speaking on Saturday Dr Glynn said: "Unfortunately our incidence has now risen to over 180 per 100,000 cases. We're reporting a five-day moving average of cases of over 800 cases per day.
"That's the highest it's been since the middle of February.
"We're seeing a particularly high incidence in people aged 16 to 30 years old and unfortunately now over the past few days we've begun to see these high cases translate into increasing numbers in hospital and in our Intensive Care units.
"I know that people have taken great hope from the fact that our vaccination program is rolling out really quickly and it's great that 60% of our adult population are now fully vaccinated.
"But unfortunately despite that at the moment we still have over two and a half million adults and children who are not fully protected or are not adequately protected through vaccination.
"And that's a really big reservoir of people who are still vulnerable to this disease over the weeks to come.
"With that in mind the key message over the coming days is for people who are not vaccinated to really be careful about indoor settings.
"If at all possibly meet up outdoors, make use of the good weather that we have at the moment.
"Do not meet up with people indoors if you can avoid it at all. And if you are meeting with others indoors make sure that those areas are well ventilated, that windows are open."
Meanwhile the Taoiseach warned that cases will continue to rise amid the Delta wave.
Speaking to reporters in Cork, Mr Martin said: "The situation is serious in regards to Delta and all of us have to be vigilant in terms of our individual behaviours because this is a further twist in the road of Covid-19 and there will be high volumes of case numbers, which will continue to grow.
"We're going to keep a very close eye on the hospitalisations that results from that and the illness that results from that.
"We want to prevent people from getting Covid, so it's important people take it seriously from that point of view.
"Quite a lot of cases develop into Long Covid or complications which we do not want and do not need."