Australia's prime minister says a shutdown of the nation's second-largest city is necessary and promised continuing financial support for businesses that fear they won't survive a second lockdown.
The Victoria state Government said Melbourne and part of its surrounds will lock down for six weeks from tonight because the rate of coronavirus spread was unsustainable.
Prime Minister Scott Morrison said the federal Government's medical advice agreed with the Victorian Government that the move was necessary.
He says "I hope it isn't for that long. I hope it's for a shorter period as possible."
Morrison says Australia's seven other states and territories would continue to relax pandemic restrictions.
Victoria authorities announced another 134 cases in the latest 24 hours.
Breaches of infection controls at Melbourne hotels where international travellers are required to isolate for 14 days have been blamed for much of the disease spread. The state Government last week responded by banning new arrivals at Melbourne Airport for two weeks.
Morrison said he wanted to reduce the numbers of Australian citizens, permanent residents and foreigners exempt from Australia's travel ban landing at Australian airports because of the strain on hotel quarantine.