Sporting events will be played behind closed doors from Boxing Day in Cymru to help control the spread of the new omicron variant.
Economy Minister Vaughan Gething announced the new measures for indoor and outdoor sporting events as the latest figures showed a further steep rise in the number of confirmed cases of the fast-moving variant.
He also confirmed a £3m Spectator Sports Fund will be available to support clubs and sporting venues affected by the new measures to protect public health.
Further details about the fund will be available following discussions with the sector.
The Economy Minister said: “Sporting events over the Christmas period are one of the big highlights of the year. Unfortunately, the new omicron variant is a significant development in the pandemic and could cause a large number of infections.
“We need to do everything we can to protect people’s health and control the spread of this awful virus.
“Throughout the pandemic we have followed scientific and public health advice to keep people safe. The advice is clear – we need to act now in response to the threat of omicron. We are giving people as much notice of these decisions as we can.
“Crowds will come back as soon as possible. We want everyone to be here to enjoy their favourite sports.”
The decision comes as some football clubs have already announced Christmas matches have been postponed because of cases of Covid-19 in their squads.
Cardiff City FC has postponed its Boxing Day match against Coventry City due to several cases of Covid-19 in its playing squad and staff. And League Two leaders Forest Green will not be playing Newport County.
The latest figures show omicron cases are rising quickly in all parts of Cymru.
The overall rate of coronavirus infections is also rising in Cymru and now stands at just under 550 cases per 100,000 people.
The Prif Weinidog last week warned of a gathering storm of omicron infections after the Christmas period as some strengthened measures were introduced from 27 December to protect lives and livelihoods.
The coronavirus regulations, including playing sports behind closed doors, will be reviewed regularly.