First Minister Mark Drakeford will announce a new limit on the number of people who can meet indoors as evidence shows indoor gatherings are the main source of transmission for the virus in Wales.
People will also continue to be encouraged to work from home wherever they can to limit person-to-person contact and local authorities will be given new powers to shut down premises and events on public health grounds.
The latest changes will come into effect on Monday (September 14) amid an increase in cases of coronavirus nationwide and the emergence of a number of hotspot areas, particularly in the South Wales Valleys.
First Minister Mark Drakeford said:
"Coronavirus is on the rise again in Wales, after many weeks of being in decline.
"Once again we are having to focus on tightening restrictions across Wales to prevent cases from rising even higher and prevent the problem from worsening – as we have seen elsewhere in the UK.
"The new measures we are announcing today are designed to prevent a new coronavirus crisis here in Wales, not respond to one.
"Wales is not immune to the spread of coronavirus elsewhere in the UK, and as difficulties deepen elsewhere, we must expect that to have an impact here, too."
From Monday, it will become compulsory for people over 11 to wear a face covering in public indoor spaces, such as shops. There will be exemptions for people who cannot wear face coverings for health or medical reasons, similar to those for public transport.
Face coverings will not be required in pubs or restaurants for the time being but the Welsh Government is carrying out a rapid review of the evidence about whether they should be extended to the hospitality sector.
The rules on face coverings are being changed because of an increase in the overall incidence rate of new cases of coronavirus in Wales, which indicates there is a serious risk of the virus spreading more widely once again.
At the moment, people are allowed to gather socially indoors with people from up to four other households, but only if they have formed an exclusive extended household (also known as a bubble).
From Monday, only a maximum of six people from the extended household will be able to meet indoors at any one time. This rule applies in pubs and restaurants as well as in people’s homes. Children under 11 will not be counted in the six.
However, this will not apply in Caerphilly County Borough Council area where stricter local restrictions have been introduced to control a sharp rise in coronavirus cases and protect public health – extended households are no longer allowed and no social meetings with anyone you don’t live with are allowed. This applies in pubs and restaurants as well as in people’s homes.
Ministers will also be giving local authorities new powers to close premises on public health grounds to tackle the spread of the virus.
First Minister Mark Drakeford added:
"We have all been through so much together this year and we all want to see an end to coronavirus but this will only happen if we all follow the rules and take action to protect ourselves and our loved ones and keep Wales safe."
To tackle the spread of coronavirus, people in Wales must: