Australia and several other countries joined nations imposing restrictions on travel from southern Africa on Saturday after the discovery of the new Omicron coronavirus variant sparked global concern and triggered a sell-off on financial markets.

But indicating that such curbs may not stem the spread of the variant, Britain said on Saturday it had detected two cases and authorities in Germany and the Czech Republic also said they had suspected cases.

Omicron, dubbed a "variant of concern" by the World Health Organisation, is potentially more contagious than previous variants of the disease, although experts do not know yet if it will cause more or less...