Ireland's Covid-19 vaccine registration portal will open for those aged 40 to 50 next week.
Chief executive of the HSE, Paul Reid, said the age group would receive communication later next week regarding their registration.
He emphasised that the vaccine rollout was continuing “at pace” and that registration on the portal was safe following a cyberattack on the health service's IT systems.
“The 40s to 50s will be next, we will be communicating out on that later next week for people to start registering on that portal,” he told RTÉ Radio’s Saturday with Katie Hannon show.
“Everybody who’s over the age of 50 to 69 can still go on now and register. We were through all of those age groups so [the portal] is now open again for everybody, and again, strongly encourage everybody [to register].”
Mr Reid said he was “soon” expecting advice from the National Immunisation Advisory Committee (Niac) and the chief medial officer regarding use of the Johnson & Johnson and AstraZeneca vaccines in those aged 45 to 50.
He said 40 per cent of the State’s adult population had now received a first dose of a Covid-19 vaccine.
“We are on target to deliver over 250,000 [doses] by the end of this week, the vaccination centres are all up and running at full steam,” he said.
“Well over two million people [are] now vaccinated, well over 1.5 million dose ones, which is 40 per cent of the adult population,” he said, adding that 11 per cent of the adult population had received dose two.
The health service was aiming to further ramp up weekly vaccinations to between 260,000 and 280,000 next week, Mr Reid confirmed.
It comes as the HSE is continuing work to bring its IT systems back online “in a safe manner one by one” following their precautionary shut down on Friday amid a cyberattack.
The HSE is working to determine the extent to which patients' medical records may have been compromised as part of the cyberattack on its systems.
No new daily Covid figures were released on Saturday due to the disruption caused by the attack.
Systems for GP and close-contact Covid-19 test referrals were among the services affected by the attack, although pre-arranged appointments are going ahead this weekend as planned.
The State’s Covid vaccination programme is also continuing, with Health Minister Stephen Donnelly urging anyone with a vaccine appointment to attend as the services goes ahead “as normal”.
Mr Donnelly also said that all Covid test and trace services were working with “some delays”.
However, thousands of patients face cancelled appointments and delays to other health services as the HSE tries to rebuild its systems.
Cancer services have been particularly affected, with many non-urgent radiation appointments cancelled. Clinically urgent in-patient and day care treatments related to cancer, haematology, dialysis, and cardiac are not affected.