Victoria's Premier Daniel Andrews has also asked those in the lockdown zones to wear face masks outside their homes.
"It was always going to get worse before it got better," Andrews said. His government has pledged another A$534 million ($565.2m) in business support measures.
Australia has limited numbers of returning citizens to 4,000 a week so that it can focus its resources on testing and tracing. Returning Australians have to be quarantined for two weeks after arrival.
Melbourne's woes paled into insignificance against developments in the US which reported new infections above 61,000 for the second day running.
New Zealand recorded another two new infections today, both returning travellers, as all the cases have been since the country came out of lockdown in May and June.
Falling share markets around the world didn't help sentiment either – in recent months the fortunes of both the kiwi and Australian dollars, which are typically regarded as a proxy for risk, have been closely linked to waxing and waning shares.
China's Shanghai Composite Index was down more than 1 per cent late in NZ's afternoon while the futures of all three major US indices were marginally weaker after a weak session on Thursday.
Mitchell McIntyre, a dealer at XE, said trading has been very quiet and it's been "a very gradual pullback in the scheme of things."
Rumours have been circulating that after the strong rally in Chinese stocks of late, Chinese pension funds have been selling.
While only rumours, "that might've introduced a tiny bit of risk aversion going into the weekend," McIntyre said.
The New Zealand dollar was trading at 94.42 Australian cents from 94.15 cents at 5pm yesterday, at 52.04 British pence from 52.11 pence, at 58.10 euro cents from 57.92 cents, at 70.05 yen from 70.61 yen and at 4.5871 Chinese yuan from 4.5969 yuan.
