The Health Minister has rowed back on a commitment to have the entire country vaccinated by September by claiming he never made such a promise.
Stephen Donnelly has also admitted that many of the new restrictions approved by the Cabinet this week have yet to be hammered out and are simply an "outline" of plans.
It is understood that a number of Ministers raised concerns around the lack of clarity and detail provided on new Covid travel measures during a lengthy Cabinet meeting on Tuesday morning.
Mr Donnelly said his recent announcement on the rollout of vaccines "wasn't a promise" as it was "heavily caveated" based on the schedule of advanced purchase.
But he added: "I said September, September is absolutely still the aspiration. It's not a promise. We can't promise for all of those reasons because it's a projection based partly on vaccinations that haven't even been applied for authorisation and on delivery schedules that still have to be fully agreed."
In an interview with RTÉ'sshow, Mr Donnelly then asked to "rephrase" his answer, stating: "If the vaccines come through that we have advanced purchases for, they're authorised and if they come in on schedule, then it is reasonable to think that by September every adult could be vaccinated, but with all of those very serious caveats."
Mr Donnelly said the plan up to March 5 is a continuation of level 5 lockdown restrictions and after that, he hopes to ramp up the vaccination programme.
When it was suggested that many of the measures announced this week, including a partial move to mandatory quarantining, had not been fully designed, Mr Donnelly said: "Well some of it is an outline but there's a lot that isn't just an outline.
"So for example, we're immediately suspending visa programmes with South Africa and Brazil, that is essentially a travel ban on South Africa and Brazil, we'll be bringing that in this week."
Mr Donnelly also admitted that the Government cannot instruct airlines to stop people getting on flights without a PCR test.
"We can't legislate for what happens in Lisbon or in the other countries but we are working with the carriers to say it is our strong preference that you refuse entry, and so very few people are arriving without the PCR test. I'm told it's about 1% who are arriving without it."
Earlier, the Minister for Public Expenditure reiterated the Government's stance against any move to zero Covid.
Michael McGrath said the Government had sought advice from Nphet on the matter but adopting zero Covid measures is "not realistic or achievable".
However, Mr Donnelly said the measures signed off on by Cabinet are almost the same as a zero Covid.
"I've met some of the people who advocated for it and we've shared ideas, and I think there's a lot of sense to a lot of what's being said.
"If you look at what we've just introduced, and you line it up, side by side with the zero-Covid list of border controls. There's really not that much difference anymore," he said.