65-year-olds can make appointments for the Covid-19 vaccination from today.
Bookings can be made online HSE.ie and by calling the special HSE phone line on 1850-24-1850.
Over 100,000 people have registered for a Covid-19 vaccination after the online portal since it went live on Thursday.
A PPS number, Eircode, mobile phone number and an email address is required to register online.
The vaccinations will start from next week and will be administered at vaccination centres rather than at GP surgeries.
People in the very high risk group 4250,000, 16-59 year olds, will also be vaccinated via a combination of vaccination centres, community vaccination teams and GPs.
HSE Chief Executive Paul Reid said the vaccination target for this week now stands at between 140,000 and 160,000 doses.
The target for the week had stood at 180,000 doses, however the target had to be revised, following the change in advice surrounding the administering of the AstraZeneca vaccine.
The HSE said that it would take three weeks to administer first dose vaccines to 65 to 69-year-olds and a further three weeks for the 60 to 64-year-olds, but that they will all be done by the end of May.