People in their 30s are expected to be able to register for a COVID-19 vaccine from next week.
The portal is currently open for 40 to 69-year-olds.
People over 70 received their jabs through a separate process, ahead of the rollout to the wider population.
A total of 3.1 million vaccines have been administered so far, officials said today.
53% of adults have received their first dose, and 26% are now fully vaccinated.
Dr Mary Favier, a member of NPHET, says she expects more progress next week.
She said: "We would hope in the next week or so the age range will come down into the 30s.
"It would be useful to remind people at this stage if they do get an appointment for vaccination to make sure they turn up, and if they can't turn up to cancel.
"[Doctors] who are working in the national vaccination centres say they're seeing a significant number of no-shows."
Earlier, Higher Education Minister Simon Harris said he expects "many, many students" will be vaccinated ahead of the start of the new college year in September or October.
