Victoria will decide on suburb lockdowns within days as the state confirmed 75 new COVID-19 cases on Monday, pushing contact tracing to the limit and prompting experts to urge tougher measures to allow the rest of Australia's economy to reopen.

It is the first time since March that more than 70 new cases have been recorded in the state in a single day, and Victoria's Chief Medical Officer warned the outbreak "will get worse before it gets better".