The Cabinet stands "full square" behind health minister Stephen Donnelly, a fellow minister has said.
Further Education Minister Simon Harris said on Monday the Government is behind Mr Donnelly, who over the weekend raised and then ruled out changing the vaccine rollout to inoculate people between 18 and 30 ahead of those in older age groups.
Mr Donnelly had asked deputy chief medical officer Dr Ronan Glynn about the plan, but told Newstalk'sprogramme that it had been dismissed.
"The short answer is no," Mr Donnelly said.
"Niac [National Immunisation Advisory Committee] in their original prioritisation identified younger cohorts as cohorts who had a higher prevalence of the disease and what they said was if the data on transmission gets to a point where vaccinations show a very significant decrease in transmission, then this group should be prioritised," he said.
The quick turnaround in the plan saw Mr Donnelly sharply criticised, but Mr Harris said the health minister is supported by the Government.
"The Cabinet stands full square behind the Minister for Health, who has an extraordinarily tough job and is doing the job of ensuring there is as many jabs in arms as possible and getting us through this horrific and difficult time."
Mr Harris said that as the minister with responsibility for students, he had not made any representations to Mr Donnelly on the subject.
"The situation around vaccines is very simple – it's not political, public health advice should be taken. It is entirely appropriate that any minister would ask any official a question.
"In relation to younger people, what I would say is that with no changes to the vaccine programme, four out of five adults will be offered their first dose by the end of June.
"We will be in a very different and better place ahead of the next college year. I'm sure we will see a very significant increase in on-campus attendance because I'm not sure it's sustainable, desirable or tenable to continue as we are."
Finance Minister Paschal Donohoe said Mr Donne
lly was "teasing out" various scenarios in relation to 18 to 30 vaccine rollout.
"Stephen was asking a question about our vaccination strategy," Mr Donohoe said.
"What every minister does when they're in a situation of conducting something that's so vital to the public and economic health in our country is they're always teasing out each scenario, challenging our assumptions – he asked a question and received advice back.
"The Government confirmed on Saturday that we're sticking with our current approach. I read about it on Saturday and to me what was important is the Government reached and issued a full clear message during the day and that's what happened.
He said "no one knows better than Stephen the importance of delivering a successful vaccination programme" and it was in that spirit that "the question was asked and equally the matter was concluded" on Saturday.
Meanwhile, the Government is expected to have a decision on extending the gap between jabs by the end of the week, according to Mr Donohoe.
"Dr Ronan Glynn and his team are examining it at the moment, effective vaccinations is the key thing within our country, we're on track to do that and our vaccination strategy is working. What I want is scale, that is now happening, it will build, and I look forward to Ronan and his team advising the Government on this decision, later in the week.
"We have evidence of what is happening in UK, Israel and America in relation to the aftermath of receiving the first dose, however, there are questions over the duration of vaccination dividend, and also questions we need to tease out regarding what impact this will have on how long we have to run our vaccination programme over the coming months.
"Undoubtedly there is important benefits of a single dose but also consequences of it, this is what Ronan [Glynn] and Brian [MacCraith] will be looking at over the week.
He said that at this point in the disease, the critical thing now is to complete vaccination efforts and that will lay the foundation for getting people getting back to work and reopening our economy.
"We have our public health experts evaluating this, we will conclude through our public health doctors this week and that will allow us to continue with the strong progress we're making in vaccinations."