A coronavirus vaccine will be ready to be used in Wales within a week of getting the go ahead, the first minister has said.
Mark Drakeford said Welsh ministers are "working on the capacity now. A lot of work has been done already".
England and Scotland have already made vaccine rollout announcements.
Plaid Cymru called for an "urgent, clear and comprehensive vaccination plan", urging the Welsh Government not to be "vague" on such a key matter.
Speaking to BBC Radio Cymru's Dros Ginio programme, Mr Drakeford said: "What other places have done is shown an ambition. What we're doing here in Wales is to plan first before we make an announcement."
A number of vaccines have recently reported successful trials but none have yet gained safety approval.
Scottish First Minister Nicola Sturgeon has said her government hopes to vaccinate a million people by the end of January, while in England they hope to have all vulnerable people vaccinated by Easter.
Mr Drakeford said:"We don't know yet, and people in Scotland don't know yet, how much of the vaccine will be available because the system hasn't yet been set up."
On Wednesday, he told the BBC Wales Live programme that If Wales were to use the Pfizer vaccine, which has to be stored at -70 degrees, that the plan is to use equipment from the Welsh Blood Service.
"We can use the equipment the Wales Blood service already has to store material at that temperature and we can make it available for this vaccine," he said.
"The vaccine will have limitations, it will be difficult to transport but we will find ways of doing it."
Plaid Cymru's health spokesman Rhun ap Iorwerth said that "seeing the kind of roll-out plans in Scotland just reinforces the need for such a clear plan in Wales". "We need to know how - once approval is given for the vaccine - the vaccine will be rolled out in Wales, including timings, recipients and logistics," he said.
What about restrictions ahead of Christmas?
Asked about plans to tighten restrictions before Christmas, Mr Drakeford insisted the "firebreak was successful" and that "it did everything we expected it to do" but acknowledged the numbers of people with coronavirus were increasing.
He said the Welsh Government was looking at what is happening in other parts of the UK to "see if there are things we can learn and if there are things we can put in place to help us with the figures we're seeing now".
"We accept that if we're going to do something in the hospitality sector then we're going to have to find more support for the sector and its supply chain," he said.
Mr Drakeford said conversations were ongoing about how to find funds to support the hospitality sector and the best way to distribute it.
He told Dros Ginio: "We're working on things today- what money can we bring together and to what purpose can we use to help things but we haven't come to the end of those discussions yet."