All employers in Wales will be told to keep workers two metres (6ft) apart from Tuesday.
Companies are being asked to take “reasonable measures” to ensure the health of staff.
But the new Welsh Government rules will not amount to a complete ban on workers being closer than the social distancing guidelines.
Ministers believe the move is necessary because of reports to trade unions and AMs of concerns from workers.
Questions have been raised over how the rules can be enforced – the law will be largely “self-policing”, First Minister Mark Drakeford has said. Mr Drakeford told BBC Radio Wales: “Almost all employers in Wales want to do the right thing, and these laws will help them to do what they want to do – to make sure their workers, their most important asset, and all the people working in their businesses are healthy and being looked after.”He added: “The eyes and ears of this rule will be the people who work in those workplaces reporting what they see to their trade union and to other authorities if they feel that these reasonable steps have not been taken.”
Rules for funerals have been relaxed to allow more mourners to attend.
Concerns have centred on a number of companies, including an outlet of pizza chain Domino’s after it denied sacking employees who made complaints.
Angharad Maddocks claimed she was dismissed in the Llanelli branch after complaining social distancing and hygiene guidance was not followed.
“Even on the make-line there’s no masks given,” she said, describing 20 people in the store “crammed together”.
Mr Drakeford has said that the new rules are not an “absolute ban” on people working closer than two metres. He urged employers to take “all reasonable measures” to ensure the health and safety of workers.
The rules will require all workplaces, businesses and organisation to take “all reasonable measures” to ensure a distance of two metres is maintained between people on their premises, and those waiting to enter.
That means companies will be expected to take “proportionate action” where it is possible to do so.
Police and councils will be able to enforce the moves, which came into force in the early hours of Tuesday morning.
The rules build on the original stay-at-home law that was introduced almost two weeks ago.
They stated people should only go out for things such as shopping for basic necessities, exercising once a day and getting medical attention.
The rules about who can attend a funeral are also being relaxed but the two-metre requirement will mean there will be a maximum limit on the number of people who can attend.
They clarify that you are able to attend if you organised it, if you have been invited or if you are the carer of somebody attending.
But there will be a limit, depending on the number of people the venue can accommodate taking into account the two-metre rule.
The guidance also clarifies that cemeteries can remain open but social distancing must be taken into account.
Local Government Minister Julie James said: “The death of a family member or friend is a very distressing event which is why we have amended these regulations to enable people to attend funerals in certain circumstances.”
She also suggested live streaming as a way of wider family and friends being part of a funeral.