By Friday, when some curbs will be lifted, the Australian city of 5 million people will have been under six lockdowns totalling 262 days, or nearly nine months, since March 2020.
Australian and other media say this is the longest in the world, exceeding a 234-day lockdown in Buenos Aires.
While coronavirus cases keep rising in Victoria state, of which Melbourne is the capital, the state's double-vaccination rate is set to reach 70% this week, allowing for the ease in restrictions. "Today is a great day," said Victoria Premier Daniel Andrews in announcing the lockdown. "Today is a day when Victorians can be proud of what they have achieved."
When hospitality venues and some businesses reopen, their capacity will remain heavily restricted. More easing, including the reopening of many retailers, will come once 80% of eligible Victorians are fully vaccinated - estimated by Nov 5 at the latest.
On Sunday, Victoria recorded 1,838 new coronavirus cases and seven deaths. Neighbouring New South Wales, which emerged last week from a 100-day lockdown, reported 301 cases and 10 deaths. Eighty percent of the state's people have been fully vaccinated.
Australia, once a champion of a COVID-zero strategy of managing the pandemic, has been moving towards living with the virus through extensive vaccinations, as the Delta variant has proven too transmissible to suppress.
The new strategy makes lockdowns highly unlikely once 80% of the population is fully vaccinated. As of the weekend, around 68% of eligible Australians have been fully inoculated.
Australia's health officials said on Sunday that quarantine-free travel from New Zealand's South Island, where there is no outbreak, will resume on Wednesday. The government is also in discussions with Singapore about reopening travel between the two countries for the fully vaccinated.
Despite the rise in cases in recent months, Australia's coronavirus numbers are low compared to many other developed countries, with just over 143,000 cases and 1,530 deaths.
Neighbouring New Zealand, which is also learning to live with COVID-19 by accelerating inoculations, reported 51 new cases on Sunday, 47 of them in the largest city Auckland, which has been in a lockdown since mid-August. On Saturday, New Zealand vaccinated more than 2.5% of its people as part of a government-led mass vaccination drive.