Ireland's National Immunisation Advisory Committee (NIAC) is expected to recommend that AstraZeneca's Covid-19 vaccine be restricted for use for people over the age of 60.
The expert group met to discuss the issue on Monday and RTE reports it is due to sign off on the issue shortly.
A formal announcement is expected later, it added.
A European Medicines Agency (EMA) investigation of blood clots in the brain reported by some people given the AstraZeneca vaccine has prompted some European countries to change their recommendations on who should be given the vaccine.
Ireland is on course to receive almost four million vaccine doses in the next three months, marking a significant boost in supply.
Taoiseach Micheal Martin said the indications from manufacturers were that Ireland will receive 940,000 doses in April, 1.2 million in May, and 1.7 million or more in June.
The Department of Health published the updated figures, which shows an increase in the number of doses of vaccines due to be delivered in the second quarter.
The department warned, however, that projected delivery schedules will fluctuate, and is dependent on manufacturers meeting commitments.
Ireland's vaccine rollout plan could see people who are in the 18 to 64-year-old cohort get appointments to receive their dose by the end of April.
As of April 8 2021, 1,045,919 doses of Covid-19 vaccine have been administered in Ireland:
- 735,997 people have received their first dose
- 309,922 people have received their second dose
Responding to the news, Labour Party Leader Alan Kelly said he has sought assurances that 80% of the adult population would be vaccinated by end of June.
Deputy Kelly said: "The latest advice due shortly from NIAC which we expect to restrict the use of AstraZeneca to over 60's raises serious questions for our vaccination programme.
"It raises immediate concerns for the hundreds of thousands of people who have already received the first dose of this vaccine if they are aged under 60. According to HSE figures 340,800 doses of Astra Zeneca were received in Ireland by the end of March but I will be seeking a breakdown of how many doses exactly have been given out, and the age breakdowns of those that received it.
"Anyone under 60 who has got this vaccine will be very worried, and needs reassurance. The government need to take control and ensure people have their concerns quickly addressed.
"We also need reassurance from the government that they still expect to be able to meet their target of offering a vaccine to 80% of the adult population by the end of June.
"813,000 doses of the AstraZeneca vaccine are due into Ireland from April to June, and some of this will be for second doses, but that means nearly half a million doses will have to go to a very specific segment of the population. That will require a very detailed rollout and logistics plan to get it to the right age cohort.
"This new advice also calls into question the role of the EMA as a regulator as they are now being undercut by national regulators. We are seeing a range of contradictory advice for this vaccine now. For example, in Northern Ireland this vaccine is being given to over 30's, while now in the Republic it will be over 60's.
"The Minister for Health needs to be able to quickly reassure the public about this latest development."
