BRISBANE: More than 10 million Australians have been ordered into lockdown as coronavirus cases spread across the country, and Brisbane on Tuesday became the fourth major city to issue stay-at-home orders. The three-day snap lockdown for Brisbane, starting on Tuesday evening, comes on top of similar measures imposed in Sydney, Perth and Darwin in recent days.

"These are tough decisions," Queensland state Premier Annastacia Palaszczuk said, after Australia recorded 23 virus cases in 24 hours.

"We are having lockdowns in major cities because the overseas arrivals are bringing the virus here."

Australia has been broadly successful in eliminating local transmission through a mix of border closures, mandatory hotel quarantine for overseas arrivals and snap lockdowns. But it is now battling flare-ups of the highly contagious Delta variant - which first emerged in India - as public anger grows at the slow pace of vaccinations. Less than five percent of adults are believed to have received both vaccine doses.