Australia announced a dramatic cut in the number of people who will be allowed to enter the country, as it struggles to contain coronavirus clusters that plunged major cities into lockdown.

With almost half of the nation's population under stay-at-home orders, Prime Minister Scott Morrison said quotas for overseas arrivals would be cut by around 50 per cent to help prevent further outbreaks.

Under the current “zero Covid” strategy, just 6,000 people are allowed to enter Australia on overseas commercial flights each week and arrivals must undergo mandatory two weeks hotel quarantine.

That quota will be cut to around 3,000 by the middle of July, Morrison indicated, although the government will at the same time step up its private repatriation flights.