WHO says the new variant carried a higher risk of reinfection than other variants.
Health unions have called for mandatory face mask-wearing in public to be reinstated immediately.
The news comes as a new COVID-19 variant named Omicron, has been identified in Belgium, South Africa, Botswana and Hong Kong.
The WHO on Friday said preliminary evidence suggested the new variant carried a higher risk of reinfection than other variants.
Scientists have also said it is the most heavily mutated version yet but are yet to determine how effective vaccinations would be against the virus.
A travel ban is currently in the process of being agreed upon in the EU from countries affected.
Downing Street has said there was nothing to suggest that England should move to Plan B restrictions, including mandatory face-masks, vaccine passes for crowded areas and guidance to work from home.
Preventing loss of life.
Chair of the Royal College of Nursing‘s (RCN) governing Council, Carol Popplestone, said; “With this variant proven to be in a neighbouring country, nursing staff are expecting swift and decisive action.
“Armed with this new information, the Government must reintroduce compulsory face coverings immediately and set out further steps in the coming days.
Ms Popplestone emphasised; “Those key early lessons must be learnt to prevent greater restrictions and loss of life.”
British Medical Association’s (BMA) Dr David Wrigley added; “The news of the variant comes at a really crucial time for the NHS as healthcare teams prepare for their most challenging time in NHS history.”
“Our recommendation has always been that people should wear masks in indoor crowded spaces, that they should adhere to social distancing guidelines, and that public buildings, offices and hospitality venues have adequate ventilation to disperse the virus as much as possible.”