MELBOURNE — Stay-at-home orders will be lifted for six million Australians in the state of Victoria Wednesday (Feb 17) after a successful five-day lockdown, allowing businesses to reopen and some spectators to return to the Australian Open tennis tournament.

Snap restrictions were ordered last Friday after a small outbreak of the more infectious UK coronavirus variant prompted fears Australia's successful battle to contain the pandemic could be undone.

The five-day closure of schools and businesses now appears to have limited the outbreak — which was linked to a quarantine hotel for overseas travellers — to 19 people, with no new cases reported Wednesday.

Snap lockdowns ordered by authorities in Australia and New Zealand appear to have worked well in controlling new waves of infections — in contrast to Europe, where restrictions have been less rigourous.

Victoria Premier Daniel Andrews said businesses and schools can reopen and residents can host small groups of visitors from 11.59 pm Wednesday, hailing the "short, sharp circuit-breaker" that got on top of the virus.

"If we had been open throughout this outbreak... total case numbers would be much, much higher and it is a certainty that I would not be reporting zero cases today," he said.

Mr Andrews had warned residents the strain was "hyper infectious", prompting fears among Melburnians who last year spent more than 100 days in a lockdown to contain an outbreak that infected thousands and killed about 800 people.

The latest five-day restrictions appear to have limited the cluster's growth to just six new cases since the lockdown began.

Mr Andrews' announcement paved the way for tennis fans to return to watch the year's first tennis Grand Slam as the Australian Open's final rounds get underway at Melbourne Park.

Tickets are now on sale for Thursday's matches, but it was unclear what restrictions would be placed on crowd sizes. 

Mr Andrews said meetings would be held later Wednesday to determine "a safe number" of attendees for the event.

"They were already were reduced but may have to be reduced further," he said of crowd sizes. "But that matter will be resolved in the next few hours."

The tournament had started three weeks late to allow international players to quarantine. 

Thousands of fans were welcomed in its first few days, before the lockdown left players slugging it out on courts in front of empty stands to reach the quarter-finals.

The latest outbreak has sparked renewed debate about Australia's system of quarantining returned travellers in city hotels.

The virus has repeatedly escaped into the wider community and caused a series of outbreaks since the country closed its international border last March.

The emergence of new, more virulent strains appears to have accelerated the problem, with targeted lockdowns also ordered in Brisbane and Perth this year.

Officials in both Victoria and Queensland states are now considering the use of purpose-built quarantine facilities at smaller regional airports, which proponents say could reduce Covid-19 spread.

Australia has been relatively successful in containing the spread of Covid-19, recording just under 29,000 cases and 909 deaths in a population of 25 million.

Many regions have been enjoying relaxed restrictions for months, with large crowds returning to sporting events at stadiums across the country.

But the problems with the Australian Open have underlined the difficulties of holding large sporting events during a pandemic, including the much more complex Tokyo Olympics, which are due to start in July after a year's delay.  AFP