Australia battles to contain Melbourne coronavirus outbreak

Australia should slow down the return of its citizens from abroad, Prime Minister Scott Morrison said on Wednesday, as the country grapples with a fresh coronavirus outbreak that has forced it to isolate its second most populous state.

The border between Victoria and New South Wales, the busiest in the country, was closed overnight and about 4.9 million-residents in the Victorian capital of Melbourne will return to partial lockdown.

Morrison said he would take a proposal to a national cabinet of state and territory leaders on Friday, seeking to slow down the return of Australian citizens and permanent residents by reducing the number of repatriation flights.

Neighbouring New Zealand announced on Tuesday that its national airline will not take new inbound bookings for three weeks to reduce the burden on overflowing quarantine facilities.

In Australia, red flags have been raised by potential quarantine breaches that the Victorian state government believes led to returnees spreading the virus. Officials have begun an inquiry.

Victoria reported 134 new infections on Wednesday, down from the previous day's record 191 but well over the low single digit daily increases of the country's other seven states and territories.

In Sydney, authorities were scrambling to track down 48 passengers who were allowed to disembark a flight from Melbourne overnight without being checked for Covid-19 symptoms.

The resurgence of the virus deals a blow to Australia's hopes of cushioning its landing as it sinks into its first recession in three decades.

Federal Treasurer Josh Frydenberg said the border closure and Melbourne lockdown would cost the economy up to A$1bn (R11,86bn) a week.

Morrison said the government would offer additional income support beyond a wage subsidy due to end in September, while Frydenberg said income tax cuts may be accelerated.

At the Victoria and NSW border, police checkpoints caused delays of more than an hour for drivers. The state line is heavily trafficked by daily commuters.

Victoria's only other internal border, with South Australia, has been closed since mid-March.

Among the new Covid-19 cases on Wednesday were 75 occupants of nine public housing towers that were earlier this week placed into complete lockdown, barring their 3,000 residents from leaving for five days.