Brook Mitchell/Getty Images State and territory health authorities are on high alert after cases of COVID-19 were detected in the Northern Territory, Perth, and Brisbane. Darwin is entering its first full day of lockdown over fears of transmission at a mine site, while new mask mandates are in effect for Perth, Brisbane, the Gold Coast, and the Sunshine Coast. NSW Premier Gladys Berejiklian told reporters on Sunday that case numbers in the state are likely to increase over the coming days. New South Wales faces an anxious wait for the latest figures from the state’s COVID-19 outbreak, while cases detected in the Northern Territory, Perth, Brisbane, and the Sunshine Coast have put the nation on high alert.