The revised Covid-19 vaccination programme will proceed with a focus on older people while any vaccines available will be used to keep up the rollout pace in the next two months.
Ministers and health officials have agreed that the same approach will be adopted for under-50s and over-50s, meaning people in their 40s could be offered AstraZeneca or Johnson & Johnson vaccines.
The plan has been discussed since last week's National Immunisation Advisory Committee (Niac) advice on the vaccines not being given to under-50s where possible, according to The Irish Times.
Officials do not believe using the two vaccines for under-50s would go against Niac's advice, as it said use should not be restricted if there are no other options available.
The Health Service Executive sent recommendations on the plan changes to Government yesterday, ahead of a Cabinet meeting today.
People aged 59 can register for the Covid vaccine on the HSE vaccine hub from today.
It is expected to take a few more weeks before the 40-49 cohort will be eligible for vaccination.
There will be some “parallel” vaccinations where doses are administered to two age cohorts at the same time, however, this will only occur when one group is being finished as another is started.
There had been some speculation that Government would move to vaccinate younger people with Pfizer vaccines while proceeding with over-50s at a slower pace.
However, it is understood that this has not been recommended due to a greater risk of severe Covid-19 illness for older people.
There is also a determination to avoid a situation where vaccines go unused while people are still waiting for a jab.
HSE figures show that just over 700,000 Covid-19 vaccines were administered in April, a good deal fewer than the target of 860,000.
Delayed deliveries and restrictions of certain vaccines due to Niac recommendations have slowed down the rollout.