Sydney's growing Covid outbreak has led analysts to say lockdown is imminent Cars swamped testing centres in the city on Wednesday and Thursday New South Wales confirmed 16 cases on Wednesday, with four mystery cases Experts believe the number of positive cases will explode in the coming days Queensland, Victoria, WA and SA have slammed their borders shut to Sydney Cafes and supermarkets across the city have also been identified as risk venues Gladys Berejiklian resisted calls to lock down, instead bringing in restrictions NSW Health Minister Brad Hazzard rubbished claims the city will be shut down