Health Minister Stephen Donnelly says officials are considering extending the gap between Pfizer vaccine doses to keep the rollout on track.
This week has seen significant setbacks to the vaccine rollout plans, just as the vaccines are set to start rolling out to more members of the public.
The online registration for COVID-19 vaccinations will open tomorrow for people aged 65-69, as the priority list shifts to an aged-based system.
It comes despite the vaccine rollout suffering a setback amid concerns about extremely rare blood clots in people who'd received the Johnson & Johnson and AstraZeneca jabs.
Johnson & Johnson has delayed its deliveries to Europe while the issue is investigated, while officials here have recommended the AstraZeneca jab should only be given to over-60s.
There are concerns the latest developments could delay the Government’s plans to have 80% of adults vaccinated by June.
Health officials are meeting senior Government ministers this morning to discuss the issue.
Health Minister Stephen Donnelly said the Government and public health officials are working ‘flat out’ to try and keep the vaccine timetable on track.
He said: "We are looking for options for how we can keep the pace of the vaccine programme going.
"Certainly extending the interval for Pfizer beyond the four weeks is something that is being looked at."
Minister Eamon Ryan also said he was confident things will remain on schedule - saying the HSE has adapted to previous setbacks in the vaccine programme.
He said: "Hopefully we'll still be on the timescale we set for this summer."
Meanwhile, the online registration system will see people aged 69 able to register for an appointment from tomorrow (Thursday April 15th).
Registration for different ages in the 65-69 category will open each subsequent day (i.e. 68-year-olds on Friday).
People will need a PPS number and Eircode to register, with vaccinations set to start from next week.