Taoiseach Micheál Martin has set a new vaccine target, hoping 70% of adults in Ireland will be fully vaccinated by the end of July.
But Mr Martin stressed that the new vaccine goal was very much dependent on supplies coming into the country.
The government had previously hoped to have 82% of adults vaccinated with at least one dose by the end of this month.
However, due to a shortage in supplies of the Johnson & Johnson single shot vaccine arriving into the country this month, it’s likely this target will not be met.
Speaking on Thursday morning to reporters, Mr Martin said: “The target, it’s all subject to supply and I have to say that strongly.
“But the aim would be to try to get to 70% fully vaccinated [by end of July].
“It’ll be challenging, it’ll be very tight.
“The recommendation by NIAC to shorten the interval timeframe for the second dose of AstraZeneca will help.
“We’ve to drive forward the vaccination programme now throughout June and July to protect our community and society in relation to not just the virus but any variants that may emerge over time.”
He also urged young people to get the vaccines.
The registration portal for those aged between 30 and 39 will open next week.
Mr Martin added: "A lot will depend on the up-take now in the younger age cohort.
“It’s very, very important that people take up the vaccine when we get an offer because if we all get vaccinated, we’ll protect each other and where Ireland has been fortunate to date is the very high level of vaccine participation rates, very high in comparison to Europe so many countries are looking at envy in Ireland.
“It’s important as we go down through the younger age cohorts that we have the same levels of participation and up-take of the vaccines as we’ve had in the older cohorts.”
Mr Martin said he met with AstraZeneca chiefs last week on the issue of vaccine shortages and said the pharma giant has developed new capacities in Spain and Germany.
He described Pfizer as “the workhouse” and said Moderna is “doing fine fulfilling its obligations and now AstraZeneca is coming in a bit stronger.”
But said the supply of Jansen is “not at all clear at this stage.”
Over the Bank Holiday weekend, the rollout passed three million doses administered, with around one-quarter of eligible adults fully vaccinated.
The Fianna Fáil leader told Newstalk that the HSE aims to see all third-level students vaccinated by the time the academic year begins.
He said the HSE will then turn its attention to the country’s teenagers.
He said: “NIAC are looking at that at the moment..some vaccines have already received authorisation on that front.
“Europe is very clear that we will be vaccinating teenagers – that is the European position – going into 2022.”
Meanwhile, Mr Martin has described the intervention by US President Joe Biden in the disagreement between Britain and the EU over how to implement Northern Ireland's post-Brexit trade rules as a “significant” development.
President Biden is to and British Prime Minister Boris Johnson will hold their first face-to face meeting on Thursday.
The Taoiseach said “we are heartened” by President Biden’s approach in relation to Northern Ireland and the Protocol.
It comes as the newly elected leader of the DUP, Edwin Poots, has said the Protocol as it currently exists, has to go.
