Prif Weinidog Mark Drakeford has tonight set out Cymru's aim to offer all eligible adults an appointment for a booster vaccine by the end of December.
"Urgent plans" have been put in place to further accelerate the booster programme as new evidence has emerged showing two doses of the Covid-19 vaccine are "not enough" to offer protection against the new omicron variant.
But the booster dose is vital in improving protection against the fast-moving variant.
In a televised message to Cymru, the Prif Weinidog said: “We must be prepared for omicron cases to rise quickly and very steeply – just as they have in other parts of the UK.
“We are still learning about this new form of coronavirus. All the information we have tells us we are facing a very serious situation. By the end of the month, omicron will have become the dominant form of the virus in Wales, bringing a new wave of infections and illness.
“This could then translate into a large number of people needing hospital treatment just at a time when the NHS is already under significant pressure. The Welsh Government will do everything we can to protect people’s health and keep Wales safe.
“New evidence has emerged about the effectiveness of our vaccines against omicron. Two doses of the vaccine is simply not enough to give the level of protection against the infection we all need. We have already increased the speed of the roll-out of our booster programme.
New clinics have been opened and operating hours extended. Urgent efforts are now underway to accelerate the programme even further so we can offer all eligible adults an appointment by the end of this year if possible.
“Please make getting a booster a priority, as it is the single most important things you can do to protect yourself against coronavirus and this new variant.”
The Prif Weinidog will add: “None of us wanted to hear the news of a new omicron variant. After almost two long years of the pandemic, we had all hoped that we could put coronavirus behind us this Christmas. Unfortunately, we are once again facing a serious and worsening situation. But, we have faced challenges many times during this pandemic.
“We can once again pull together to look out for each other – for friends, family and neighbours – to protect each other and keep ourselves safe and well. We have already taken some steps to increase protections in Wales and we may need to take some further steps to keep Wales safe.”