Employers in Wales will be breaking the law from next week if they do not make sure that staff are able to maintain the 2-metre physical distancing rule.

The Welsh first minister, Mark Drakeford, made it clear he did not want companies to be shut down but said it was vital that they put the welfare of their employees first.

Employees across the UK in workplaces including call centres, factories and building sites have expressed concern that they are unable to stay a safe distance from colleagues.

Drakeford said the Welsh government had listened to workers’ fears and would be the first in the UK to bring in a new law requiring employers to take “all reasonable actions” to comply with the 2-metre rule.

The first minister said the regulations would come into force on Monday or Tuesday next week and fresh guidance would be issued to make sure that employers understood what was being expected of them.

He said: “It is simply saying to employers they must put the needs of their workforce first. Their health and well-being must be top of the agenda.

“We’ve heard the messages coming from some people saying they are fearful at the way their health is being compromised in the workplace.”

The GMB union welcomed the move and called on the UK government to follow suit.

Dan Shears, GMB health, safety and environment director, said many employers had so far ignored the rule. “Those companies will now need to fall into line or fear the consequences.”

He added: “Where the job of work does mean being closer than 2 metres – nursing, care, education, undertaking to name a few – the guidance will need to give clear principles on how this can be safely done by employers carrying out full risk assessments, identifying the correct PPE [protective personal equipment] and ensuring that it’s given.”

Robert Lloyd Griffiths, of the Institute of Directors Wales, said: “Employers should be doing what they can to help stop the spread of the virus.” But he added: “It’s important firms have the support and clear guidance in place to put these rules into practice.”

The mayor of Greater Manchester, Andy Burnham, was among those who has highlighted concerns, saying companies are “nowhere near observing” distancing rules. He said he had been contacted by more than 300 members of the public, highlighting concerns at about 150 companies.

The online fashion chain Asos has been criticised by staff who say they are scared to attend work at its distribution centre because they are not being sufficiently protected.

The TUC general secretary Frances O’Grady said: “We welcome the action from the Welsh government to improve protection of workers through social distancing. The UK national government must make sure that all UK workers have proper protection, if businesses remain open they must apply the guidelines that have been issued by Public Health England.”