Mandatory social distancing will also be introduced for office workers
Wales is set to see a return to tougher Covid restrictions after Christmas following a surge in Omicron cases in the UK.
The First Minister has announced a mixture of advice for over the Christmas period alongside new regulations to follow as part of a “two-phase plan”.
Nightclubs will be closed from December 27 under the new rules, although the Welsh Government has announced a £60 million fund to support any businesses affected by the restrictions.
From the same date, two-metre social distancing will be mandatory in offices, and measures including one-way systems and physical barriers will be introduced in businesses to protect customers and staff.
Regulations will also be changed to include a requirement to work from home wherever possible.
Until December 27, the Welsh Government is encouraging people to follow five steps, including getting vaccinated, making sure to have a negative lateral flow test result before going shopping or meeting people, meeting in well-ventilated areas – preferably outdoors, spacing out socialising to allow test days in between, and adhering to social distancing, wearing a face covering and washing hands.
It is also urging people to reduce contact with others over the coming days, especially if Christmas plans include seeing older or more vulnerable people.
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.
“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 changes for businesses comes with the announcement that up to £60 million will be available to support those affected by the new measures.
He added: “This year a smaller Christmas is a safer Christmas. The fewer people we see, the less chance we have of catching or passing on the virus.
“Please enjoy Christmas with your nearest and dearest – and think about meeting up with wider circles of friends when the threat posed by the Omicron variant has passed over.
“I also want to thank the many thousands of people who will be working this Christmas to keep us safe – especially all those who have cancelled their plans to work in the vaccination centres across Wales to increase our protection against this awful virus.”