People at very high risk, or high risk, of Covid-19 due to underlying conditions can register for their vaccination from tomorrow, if they are aged 45-49 and have not yet got an appointment from their hospital or GP.
Registration will also open for health staff within this age group who have not got an appointment through their workplace and for people who do not have a PPS Number.
The registration will also open for the 45-49 age group, starting with those aged 49. Registration will be available for people aged 48 on Thursday, 47 on Friday, 46 on Saturday and 45 on Sunday.
All of the people in these various groups will get an mRNA vaccine, either Pfizer or Moderna.
Work is ongoing at the Health Service Executive around use of the Johnson and Johnson (Janssen) vaccine.
The HSE says that the vaccinations will be administered later this month and in June.
Registration can be done online or by phone.
The HSE also said people in the high-risk and very high-risk categories are being vaccinated through their GPs.
It added that there is no change in the approach to the high-risk and very high-risk people in this category, compared to those in any other age group.
Speaking on RTÉ's News at One, Minister for Health Stephen Donnelly said the vaccine programme's computer system, which is a new system, has not been compromised in the cyber attack on the HSE and the programme is moving very quickly.
He said there has been no indication that it has been compromised at all.
He said two in five adults have now received a first dose and last week was a record week, with about 50,000 vaccinations administered in one day last week.
Earlier, the HSE's Chief Clinical Officer said the executive has received advice from National Immunisation Advisory Committee that people aged 40 to 49 could receive Johnson & Johnson and AstraZeneca vaccines.
Dr Colm Henry said the HSE will see if this advice, and conditions attached to it, can be reconciled to the vaccination programme, which is ramping up in scale and gathering pace.
Dr Henry said the priority is safety, but "getting through the age groups is clearly a priority as well".
He told RTÉ's Morning Ireland that medical experts are agreed that the best vaccine you can get, is the one you are offered first.
Pandemic legislation extended until November
The Cabinet has extended emergency pandemic legislation, which includes additional garda powers, until 9 November.
The request was made by Minister Donnelly and approved by Cabinet unanimously.
A Government spokesman said Mr Donnelly felt the public interest would be best served by their retention.
The Cabinet decision will go back to the Oireachtas "as soon as possible" for confirmation.
Cabinet also agreed that the minister will bring a motion before the Oireachtas to extend Mandatory Hotel Quarantine.
Unlike the emergency pandemic legislation, the extension time has still to be determined.
358 cases reported by Department of Health
There have been 358 cases of Covid-19 reported by the Department of Health this evening.
There are 102 people with the disease being treated in hospitals, with 39 of these people receiving intensive care.
The Department of Health, which is dealing with the fallout from a cyber attack last week, has said the numbers are subject to future data validation.
In Northern Ireland, the Department of Health has reported two further coronavirus deaths and 104 new cases of the disease.
There are 38 confirmed Covid-19 patients in hospital, with three in intensive care - all of whom are on ventilators.
Additional reporting Mícheál Lehane