Sinn Féin's health spokesperson has said that there is a "lack of detail" around Ireland's Covid-19 vaccination strategy.
David Cullinane expressed concern around staffing levels and infrastructure.
His comments follow a briefing he attended today with experts involved in coordinating mass inoculations.
The briefing was attended by Professor Brian MacCraith head of Ireland's Covid-19 Vaccine Taskforce, Professor Karina Butler, chair of the National Immunisation Advisory Committee, and Dr Colm Henry, Chief Clinical Officer with the Health Service Executive.
Mr Cullinane said that he could not get clarity on how many staff will be needed to administer vaccines.
He said that 180 community vaccinators are currently administering vaccines to those in nursing homes and residential care facilities.
This is being done on a five day a week basis, with a HSE commitment to increase this to seven days a week, but Deputy Cullinane said: "We need to see the evidence of that".
There are 1,700 hospital staff delivering the vaccine on a "peer-to-peer" basis.
Mr Cullinane said that 15 mass vaccination centres have been promised, but as of this morning just one site has been identified and "they still have no detail in relation to the other centres".
Two thousand people are undergoing training to administer vaccines which the deputy said was welcome, but he said he could not get a clear answer today on how many vaccinators will be needed in total.
He welcomed news that the European Commission has agreed a deal to double its order of the Pfizer/BioNtech vaccine.
Social Democrats co-leader Róisín Shortall expressed concern that the HSE is not prepared to ensure enough staff are in place to administer the vaccinations.
In a statement, she called on Minister for Health Stephen Donnelly to clarify the staff numbers required and where the vaccinators will come from.
She said the HSE "would appear to be relying on school vaccinators, who currently work limited hours, as well as what are termed 'peer vaccinators' in hospitals".
Ms Shortall said the HSE needs to be given approval to open recruitment for vaccinators for suitably qualified staff.
She said it would be "unforgivable" to find ourselves in a position with sufficient quantities of vaccine doses but not enough staff to administer them.