South Africans intending to travel to the US beyond 30 January will be denied entry into the country.
On Monday, The White House confirmed President Joe Biden has signed a COVID-19 travel ban order, fearing the spread of the more infectious variant known as 501Y.V2.
The ban applies to South Africa, but it also includes Brazil, Ireland, the United Kingdom and 26 other countries in the European Schengen.
Only US citizens are exempt, but they will still be subjected to COVID-19 testing and quarantine measures.
The new travel restrictions come as Minnesota recorded the first US case of the Brazil variant from a resident who had visited the South American country.
Former President Donald Trump had ordered the bans to end on 26 January as one of his final acts in office.