Serious doubts have been cast over Health Minister Stephen Donnelly's promise to have everyone vaccinated by September after it was claimed the numbers "do not add up".
The Health Minister has admitted that a "significant" number of nursing home staff and residents will not be vaccinated before Sunday's target due to outbreaks of the virus.
Fianna Fáil TD Marc MacSharry hit out at Mr Donnelly's "continuing headless chicken approach" after the minister pledged to have all people vaccinated by September.
While Mr MacSharry said the commitment was "great news", he questioned how this would be done, given there was still uncertainty around the delivery schedule of vaccines.
"The supply chain that is available to us and the vaccines that are available to us do not add up to meeting that sort of deadline."
He called on the minister to "get on the phone" to AstraZeneca, Pfizer, Johnson & Johnson and Moderna to secure additional supplies.
"There are no gold medals for being good Europeans on this one," Mr MacSharry said, adding that if they want €70 a dose the Irish Government should pay that.
Calling for full transparency and proper communication in relation to the rollout, Labour health spokesman Duncan Smith also queried how Mr Donnelly expected to have all residents vaccinated and pointed to discrepancies in the figures provided.
"As of 13 January, 69,700 frontline healthcare workers had received a vaccine, according to the HSE's figures. The minister stated, however, that as of Sunday next, 24 January, a target of 140,000 will have been reached, split more or less evenly between healthcare workers and people in nursing homes and their staff.
Mr Donnelly told the Dáil that about 94,000 people had received the first dose of the vaccine by last Sunday and "at the end of this week, our most vulnerable citizens – those in long-term residential care – will have received the first dose of the vaccine.
"As a nation, we should all be really proud of this."
But responding to Social Democrat co-leader Róisín Shortall, he admitted there were "outliers where there will be residents who, because they have Covid-19, cannot be vaccinated".
The HSE has listed 6,551 people working or resident in care homes on their vaccine plan for next week, however, it is understood this number could increase as outbreaks have halted the rollout in some homes.
Mr Donnelly admitted his plan to get delivery of the "game-changer" vaccination from AstraZeneca ahead of approval from the European Medicines Agency (EMA), is not possible and it is now likely to be mid-February before we take delivery of the drug.
The minister last week said he was working to get the vaccine into the country to have it ready for rollout immediately after the EMA approval, which is expected on January 29.
He said this may not now be possible because "anything that is brought forward has to be done on a full, commission basis".
"A country cannot get special treatment as a single member state."
Meanwhile, Mr Donnelly has clarified that the plan to vaccinate everyone in the state by September does not include children.
Speaking on Newstalk's The Hard Shoulder, Mr Donnelly said: “It is not about being a citizen, obviously. If you are living here you will be offered a vaccine and you will be offered it for free.
“At the moment the vaccines we have are for adults. The Moderna one I think is 17 up. Pfizer, I would have to check absolutely, but for the moment it is adult residents."
Mr Donnelly warned that the timelines were, however, "super preliminary".