The city takes the title from Buenos Aires after entering its 246th day under stay-at-home orders on Monday.
Premier Daniel Andrews has marked 26 October as the day Victoria’s coronavirus restrictions will ease considerably, with the state predicted to hit the 70 per cent double dose milestone around that date.
By then, Melburnians will have spent 267 days under lockdown, which is 45 per cent of the time since the pandemic began.
Victoria recorded its highest daily COVID case number on Saturday with 1448 new infections.
“We are going to get past this. We are going to end this lockdown and open up, and all that we will enjoy then will be a result of all that we have given,” Andrews told media on Sunday.
Dublin comes in third place for the most locked down city behind Buenos Aires, having spend 227 days in lockdown, followed by London at 201 days.