Australian leaders have urged caution but called for a measured response after the new Omicron variant of Covid-19 emerged. The country stopped flights from nine countries in southern Africa while some states reintroduced quarantine for returning travellers from particular regions. The prime minister, Scott Morrison, has ruled out closing the international borders to citizens, while NSW premier Dominic Perrottet warned against any ‘kneejerk’ reactions as restrictions begin to lift across the country
