Wales has made it illegal for people to go to work unnecessarily under its latest Covid-19 restriction measures, but legal for people to go shopping.
It means those breaching the rules face a £60 fine.
The government has amended legislation to make attending a workplace unnecessarily a criminal offence, amid the spread of the Omicron variant.
It comes as the number of identified Omicron cases in Wales grew by 204 on Tuesday to 640.
On Wednesday, the Welsh government recalled its parliament amid soaring coronavirus cases in the country and announced tougher restrictions to start on Boxing Day.
The nation has amended its legislation stating that “no person may leave the place where they are living, or remain away from that place, for the purposes of work or to provide voluntary or charitable services” when it is “reasonably practicable” to do so from home.
It adds that anyone who contravenes this rule “commits an offence” punishable by a fine of £60.
However, people in Wales are still allowed to leave home to visit pubs and restaurants, and there is no limit on household mixing.
The latest restrictions in Wales also include the closure of nightclubs from December 27, and compulsory distancing through measures such as one-way systems in businesses to protect customers and staff.
From December 26, sporting events whether indoors or outdoors will be played behind closed doors.
“We are facing a very serious situation in Wales. A wave of infections caused by the new, fast-moving and very-infectious Omicron variant is headed our way,” First Minister Mark Drakeford said.
“This new form of coronavirus could infect large numbers of people in Wales, disrupting daily lives and businesses, and could cause an increase in the number of people who need hospital care in the coming weeks.
“We will do everything we can to protect people’s health and livelihoods in Wales – this means taking early action to try and control its spread.
“We are changing the rules for businesses and some public spaces, where lots of different people mix daily, and issuing strong and clear advice to help people stay safe in their own private homes and when meeting others.”
From Boxing Day there will be two-metre social distancing in all premises open to the public and workplaces, a rule of six will apply to gatherings in regulated premises, such as hospitality, cinemas and theatres, and all licensed premises will have to reintroduce table service.
On Wednesday, the UK Prime Minister Boris Johnson reduced the self-isolation period for fully vaccinated people who have coronavirus in England to a week and reassured the public that Christmas will be able to go ahead without further restrictions.
He said those who receive negative lateral flow results on day six and day seven of their self-isolation period, and are vaccinated, will no longer have to self-isolate for the full 10 days.
The rule change may help thousands of people see their families in time for Christmas.
It came after the prime minister said “continuing uncertainty” about the severity of the Omicron variant and hospital admission rates means he does not believe there is enough evidence at the moment to justify stricter measures.
However, he stressed the situation remains “finely balanced” and did not rule out introducing stricter measures soon after Christmas.