Thousands of people in Sydney's northern beaches area have been warned to stay home after a COVID-19 cluster grew to 17 infections. "As a number of new cases are currently being interviewed, it is likely that a number of new venues will be identified and that people in the northern beaches may have attended these venues," NSW Health said in a statement on Thursday night. To assist contact tracing and to contain any potential spread of COVID-19, people have been asked to work from home and stay there as much as possible for the next three days. They have also been urged against visiting friends or relatives in aged care facilities or hospitals unless it is essential.