Wales will introduce new social distancing measures and close nightclubs from 27 December 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.
The Welsh government announced that up to £60m will be made available to support affected businesses which will also include a two-metre rule on social distancing in offices and putting extra measures in place to protect customers and staff, such as one-way systems and physical barriers.
First minister Mark Drakeford said: “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.
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.”
Michael Kill, chief executive of the Night-Time Industries Association (NTIA) said: “We are astounded at the actions of the Welsh government this evening, the consistent targeting of the nightclub and late night economy sector has gone too far.”
“It is very clear that the Welsh government have purposefully placed restrictions on an industry with no supporting evidence.
“Nightclubs and the late night economy have been at the sharpest end of the pandemic, and have upheld the public heath strategy within Wales for over two years, with closures and mounting debts.
“We have been placed in an untenable position and will now have no choice but to come out fighting.
“The sector will be considering its legal options following this announcement.”
Despite telling people to curb socialising plans this festive season, no support has been announced for pubs, restaurants and other areas of hospitality which have seen huge numbers of cancellations at what should be their busiest time of year.