Malawi, Mozambique, Zambia and Angola have been added to the travel red list for arrivals into England as fears over a new variant of Covid-19 grow.
They join a number of African countries on the list, including South Africa, Botswana and Namibia.
As a result of the decision, British and Irish citizens, or those with residence rights, arriving to England from countries on the red list must book a managed quarantine hotel in advance.
The package will include a the nights in a hotel, quarantine transport and a test package for Covid-19 on day two and day two of quarantine.
Prime minister Boris Johnson also confirmed earlier all arrivals in the UK would need to undergo a PCR test as authorities seek to slow the spread of the Omicron variant.
Two cases of the variant have already been identified in Essex and Nottingham.
Targeted testing and contact tracing is now underway, the government said.
Early indications suggest this variant may be more transmissible than the Delta variant and current vaccines may be less effective against it.
A rapid rise in infections in South Africa has been attributed to the spread of this new variant of Covid-19.
Rory Boland, Which? Travel editor, said the situation remained fluid: “This news is a further reminder that travel is not back to normal, and that the pandemic will continue to throw travellers’ plans into jeopardy, often at short notice.
“All flights are suspended to these four countries, so passengers will be entitled to a refund for their holiday or flight, so long as they booked with a UK or EU carrier, or with any carrier due to depart from the UK or EU.
“However, getting refunded for the cost of accommodation will be trickier, and will depend on the property’s policy.”
He added: “If your trip is several weeks or months away, travellers should at this stage do nothing as the situation may change.
“Those booking a trip should do so through holiday providers with good, flexible booking policies in case it cannot go ahead.”