Wales will introduce new social distancing restrictions and close nightclubs from 27 December in a bid to slow the spread of the Omicron coronavirus variant.
The new tougher restrictions will also affect businesses and services and include extra measures to protect customers and staff – such as one-way systems and physical barriers.
The rules will also be changed to include a requirement to work from home wherever possible.
People are advised to follow five steps for a “safer Christmas”, before the new rules come into force.
First Minister Mark Drakeford said: “Delta will continue to be the main cause of coronavirus infections in Wales up to Christmas. But we are seeing cases of omicron increasing rapidly every day in Wales – and across the UK.
“We need a plan to keep us safe this Christmas and we need stronger measures to protect us afterwards, as we prepare for a large wave of omicron infections.
COVID-19: Schools urged to ask ex-teachers to return to fill coronavirus absences
COVID-19: Boris Johnson faces fresh claims of Downing St party held during May 2020 lockdown
COVID-19: Wolverhampton hospital braces for spike in patients – as woman who put jab on ‘back burner’ urges others to get vaccine
“Omicron poses a new threat to our health and safety. It is the most serious development in the pandemic to date.
“It is one we must take seriously. We will continue to put in place proportionate measures to protect people’s lives and livelihoods.
“This is a virus which thrives on human contact. Every contact we have is an opportunity for us to spread or catch the virus.”
The Welsh government has announced up to £60m will be available to support businesses affected by the new rules.
It comes after the Welsh government cabinet met twice today to decide how to tackle the new variant, amid alarm at growing case numbers in the UK.
Dr Frank Atherton, chief medical officer for Wales, had previously advised the people to reduce their social contacts.
“We absolutely need to prioritize what we want to do at Christmas, for me, it’s about seeing family,” he told BBC Wales.
“It’s not about going to the pub, it’s not about going to a nightclub, it’s not about going anywhere that’s crowded or indoors.”
On Thursday, Wales reported a further 2,889 COVID-19 cases and 33 of Omicron.
Please use Chrome browser for a more accessible video player
This brings the total number of cases of the new variant in Wales to 95, a rise that is in part due to the change in how the strain is classified.
However, Dr Meng Khaw, from Public Health Wales, said “a rapid increase over the coming days and weeks is expected”.
Last week, health minister Eluned Morgan warned new restrictions were “likely” in the face of the “tsunami” of infections from the Omicron variant.
In last Friday’s three-week review, First Minister Mark Drakeford announced reviews would now take place weekly due to the threat posed by the Omicron variant.
He has urged people to get a booster vaccine and the number of vaccination clinics have increased with opening hours extended.