More than 30,000 people received a COVID-19 vaccine at walk-in centres over the long weekend.
It was predominantly younger people who received the jab, although an 83-year-old turned up at a centre in Co Sligo.
While another vaccine slot is open at a centre in Tralee on Tuesday from 11.00am to 3.00pm.
The HSE's chief clinical officer Dr Colm Henry says some centres had to open early to deal with the demand over the weekend.
He told Newstalk young people are making "extraordinary efforts" to shore up Ireland's vaccine "floodwall".
Bank holiday Monday was the busiest day for the centres, at around 11,000 people.
The HSE's national lead for the vaccination programme, Damien McCallion, told Newstalk Breakfast they may open them again.
"We're still finalising some of the numbers coming through from some of the centres, but broadly speaking yesterday was our busiest day.
"And it was good to see over the weekend - even on Friday where we only had a small number of clinics in some of our other locations - the uptake in those areas was really, really good.
"So it's certainly something we'll look at again, we'll evaluate it today.
"We'll look at how it worked, we'll take the feedback from the locations, we'll also look the people who are remaining".
He says the main objectives have been achieved.
"One of the objectives of the walk-ins was to try and see whether we could attract people as well who, perhaps previously, hadn't engaged with the programme and weren't registered.
"And we found good uptake - indicative numbers would suggest that nearly as close as half the people who attended the walk-in clinics over the weekend were people who hadn't previously registered.
"There was an option for people who were registered but hadn't yet got an appointment to come in as well.
"So overall we're very happy with it, it was a good initiative... it has worked very well over this weekend".