The MCG has been named as a potential COVID-19 acquisition site after a man who attended both the Boxing Day test and post-Christmas sales at Chadstone Shopping Centre tested positive to COVID-19, prompting warnings from health authorities that Victoria is "most likely" facing a fresh virus cluster.

Eight thousand cricket fans and "many thousands" more Boxing Day shoppers are potential close contacts of the man, who is in his 30s, whose original infection source is unknown.