The National Immunisation Advisory Committee (NIAC) is expected to recommend that the AstraZeneca vaccine be administered only to those over the age of 60.
According to RTÉ News, an official announcement to that effect will be made later today.
The NIAC met this morning and a further meeting is currently underway to sign off on the issue.
The group will pass their recommendation on to Acting Chief Medical Officer Dr Ronan Glynn who will then report the advice to the Government and then the HSE.
The guidance on the AstraZeneca vaccine has been issued following blood clot concerns in younger people.
The European Medicines Agency (EMA) last week confirmed a link between the vaccine and very rare blood clots, but stressed the benefits of the vaccine outweigh the risks.
A number of European countries have decided not to give it to younger age cohorts after reports of rare blood clots.
Speaking ahead of the NIAC decision, HSE chief Paul Reid told South East Radio that the evidence from the EMA is that the vaccine is safe.
Mr Reid said the AstraZeneca vaccine is still a key part of the HSE's vaccination plan and is still a very effective vaccine.
"It is still one of the major tools in our armour against this pandemic. It is a very well-proven, effective vaccine," said Mr Reid.
He said that any changes to where the vaccine should be rolled out will be made based on the recommendation from NIAC.