Health Minister Stephen Donnelly has said that everyone should receive their second shot of the AstraZeneca vaccine by July 12.
Earlier this week, Ireland received around 600,000 additional doses of AstraZeneca and Pfizer vaccines.
During an interview with RTE's Morning Ireland, Minister Donnelly confirmed that it won't be the case of one cohort receiving the majority of the vaccines and both cohorts will be cared for.
NIAC's recently updated advice has recommended the use of AstraZeneca and Johnson & Johnson jabs for those under 40.
Minister Donnelly said: "What we're doing with a lot of that amount that has come in is we are accelerating the end of dose two of AstraZeneca, for 60 to 69 [year olds] but also for all of the other cohorts who've had their first dose of AstraZeneca.
"Our intention is that in about the next 10 or 11 days, everyone who has had their first dose of AstraZeneca - or if they haven't already haven't had it already - they will have their second dose of AstraZeneca."
The original target for all of the second doses of AstraZeneca to be administered was originally July 19 but plans have been accelerated due to the growing threat of the Delta variant.
Minister Donnelly also provided an idea of the overall number of doses that health authorities will be looking to administer to this cohort in July.
He said: "We're moving it forward and we can do this because the NIAC advice has changed to four weeks. Then for July, what we have sight of is about 100,000 more AstraZeneca doses.
"When we've done all of that group (dose two for people who want it), we can then go for people who want dose one, we've about 100,000 AstraZeneca, and about 205-210,000 Janssen, so a little over 300,000 in July and then obviously more in August."
Minister Donnelly was also confident that the HSE IT systems can cope with this extra demand, especially considering the recent cyberattacks that they've endured.
"The IT systems are in place, so whether you go through the normal mRNA portal, or you go through the portal and get AstraZeneca in the vaccine centre or, indeed, you go to the pharmacy, the vaccine system will record your details. That will all be there," he said.
The Health Minister also said that Ireland will be ready to join fellow EU members states in the vaccine certificate programme on July 19.
