The HSE will launch its online vaccine booking system in two weeks time.
Members of the public will be able to register on the portal from the week starting April 19th.
Those aged between 65 and 69 will be the first to use the system.
HSE CEO Paul Reid explained: "When people in that age group will register, they'll register some biographical details on the portal.
"They will get a combination of email and text message back to validate their details... they'll do that, and they're then registered."
He said they will deal with cases where people do not have access to the internet.
Within that first week of registration, the HSE will start work on vaccinating people in the 65-69 age group.
Mr Reid said the mass vaccination centres will be scaled up throughout the month - from the 14 currently in operation to 30.
The Government has today also revealed that Ireland is currently estimated to be in line for a total of 3.9 million vaccine doses over the next three months.
Over two million of those are set to be the Pfizer / BioNTech vaccine.
The Government adds that the current schedule is subject to change "based on manufacturers yield outputs and final confirmed delivery schedules".
In contrast, Ireland received just over 1.1 million doses in the first quarter of the year.
The Government has said it hopes that at least 82% of the adult population will have received at least one dose of a vaccine by the end of June.
Meanwhile, the Taoiseach today said there are no plans to change the vaccine rollout list.
It comes as three major teachers unions today backed a motion up to possible strike action over changes to the priority list.
While the vaccine rollout is set to move to an age-based system once vulnerable cohorts are vaccinated, the ASTI, TUI and INTO say teachers should be prioritised.
However, Micheál Martin says the government will stick to official advice.
He said: "From the outset, we've been guided by NIAC's advice... and we'll continue to be.
"To deviate from that now I think would be very, very problematic."