The new variant of coronavirus currently sweeping across parts of England is also a factor in the rapid rise of cases in Wales, a minister has said.
Wales’ health minister Vaughan Gething told BBC News On Sunday that the new variant was “effectively seeded” across the country.
Mr Gething added: “Unfortunately our rates are around about 600 per 100,000, they are very high across the country with large concentrations in the south of Wales but also north-east Wales has been particularly affected as well.
“This has been a very difficult decision for many people here in Wales, I know people have been frustrated and there are some people who are angry but we are having to make these choices to try to keep people safe.
“We have already moved ahead of the rest of the UK in changing our rules about Christmas mixing when new information about the new variant, and the fact it does appear to be generating a much more rapid growth of the virus, really does mean that we need to act.”
“The undoubtable truth is this new variant is effectively seeded across the country, so acting now takes account of the fact that this new variant is undoubtedly a factor, we can’t say how much of a factor, in the rapid growth in cases across south Wales despite the measures we have taken.”
First Minister Mark Drakeford announced on Saturday that an immediate lockdown in Wales was needed to protect people from the new strain.
Wales was due to move into its Level four of restrictions, the highest level available, from December 28, with non-essential retail, close contact services, gyms and leisure centres and hospitality due to close over Christmas Eve and Christmas Day, but Mr Drakeford said it would do so at end of trading on Saturday.
Plans to allow five days of relaxed restrictions allowing up to two families to form a festive bubble have also been cut short and will now only apply for Christmas Day.
People must also now work from home if possible, while stay-at-home measures will apply from midnight.
In a statement on Saturday the chief medical officer for Wales Dr Frank Atherton said that there was “rapidly emerging” evidence the new variant appeared to be “significantly more transmissible than the wild type virus”.
He said, despite a small sample size, an Office for National Statistics (ONS) study showed that the new variant could be responsible for up to 60% of new infections in Wales.
Dr Atherton added: “Emerging public health advice suggest that the new variant is at least contributing to, and possibly driving, this growth rate.
“Given the risk of further high growth continuing, to contain the harm of the pandemic and prevent already strained NHS resources from being overwhelmed Level 4 measures will need to be brought forward as soon as possible.”