People aged 59 can register online for a Covid-19 vaccine from today.
The HSE online portal will then open to others aged 50-59 on a phased basis later this week.
HSE chief executive Paul Reid said clarity would be provided to other age groups on when they can expect a vaccine in due course.
Vaccine rollout plan
The HSE has sent recommendations on changes to the country's Covid vaccine rollout plan to Government, ahead of a Cabinet meeting today.
The revised 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.
All remaining construction can recommence from today as part of the first date earmarked in the Government's plan to ease Covid restrictions over May and June.
Outdoor workers like window cleaners and maintenance staff can also return to work.
A further major easing of restrictions will take place on May 10th, when intercounty travel will resume, three households or six people will be able to meet outdoors, and a vaccine bonus will come into force.
The cost of alcohol will soon rise if the Government approves the implementation of minimum pricing for alcohol today.
Minister for Health Stephen Donnelly will seek approval for the scheme, which could see the price of a bottle of vodka increase by up to €7.
It is understood Mr Donnelly hopes to introduce minimum unit pricing in the coming months in order to "reduce the health harms of alcohol" by preventing the sale of strong alcohol products at very low prices.
Three suspects have been arrested for questioning about the murder of a teenager in Co Louth last year.
The latest arrests in the ongoing investigation were made on Monday morning and come as one man is already before the courts in relation to the killing.
The murder victim, who was a juvenile, cannot be named for legal reasons. In a statement Garda Headquarters, Phoenix Park, Dublin, said his murder occurred in Drogheda in January last year.