SYDNEY • Australia and New Zealand have moved to seal off their borders, announcing unprecedented bans on entry for non-residents in the hope of stemming the rise of Covid-19 infections.

The announcement came as Australia's biggest airline Qantas said it would halt all international flights for at least two months and suspend two-thirds of staff, while the country's central bank cut interest rates to record lows.

Australian Prime Minister Scott Morrison said the ban on anyone who is not a citizen or permanent resident coming to Australia will be in place from 9pm local time (6pm Singapore time) today.

"The overwhelming proportion of cases in Australia have been imported," he said at a televised briefing in Canberra.

A similar measure - which kicked in from midnight yesterday - was announced by his New Zealand counterpart Jacinda Ardern.

"I recognise how extraordinary this is. In no time in New Zealand's history has a power like this been used," she acknowledged.

The two countries had already imposed restrictions to tackle the pandemic, but have so far stopped short of closing schools or instituting wider-ranging lockdowns. Policymakers hope the bans will slow the rate of infection enough to avoid more draconian measures that would cripple the economies and transform life for months to come.

Australia has 709 confirmed cases, with the total doubling roughly every three days. New Zealand has 28 cases.

Mr Morrison said around 80 per cent of Australia's cases came from someone who has contracted the virus overseas or someone who has had direct contact with someone who has returned from overseas.

A recent opinion poll showed 69 per cent of Australians back closing the border.

Earlier, Qantas said all of its international flights would be suspended by late this month for at least two months. "The efforts to contain the spread of the coronavirus have led to a huge drop in travel demand, the likes of which we have never seen before," Qantas chief executive Alan Joyce said, adding that the airline would suspend 20,000 of its 30,000 staff during the shutdown.

The move also affected Qantas' budget offshoot Jetstar.

The Reserve Bank of Australia, the country's central bank, yesterday cut interest rates to a record low of 0.25 per cent.

At least A$90 billion (S$75 billion) will be provided to support small and medium-sized businesses.

AGENCE FRANCE-PRESSE, REUTERS