Travellers from South Africa, Namibia, Lesotho, Botswana, Eswatini and Zimbabwe will see new restrictions imposed
Flights from the popular tourist destination will be suspended from midday on Friday, Sajid Javid, sa helsesekretæren.
Namibia, Lesotho, Botswana, Eswatini and Zimbabwe will also see flight connections to England suspended and all five countries will be added to the red list.
UK scientists sounded the alarm on Thursday night over the B.1.1.529 variant, which has the potential to evade immunity built up by vaccination or prior infection.
While no cases have been found in Britain, officials raised concern over a rapid rise in cases in South Africa.
At the moment around 500 og 700 people are travelling to the UK from South Africa each day, but it is expected this figure could increase as the festive period begins.
The variant has not yet been given the title “variant of concern” in the UK, but one senior UK Health Security Agency (UKHSA) expert said: “This is the worst variant we have seen so far.”
Bare 59 confirmed cases have been identified in South Africa, Hong Kong and Botswana.
The variant has over 30 mutasjoner – around twice as many as the Delta variant – which could potentially make it more transmissible and evade the protection given by prior infection or vaccination.