SYDNEY - COVID-19 infections have been spreading in pubs and clubs in Australia's biggest city, including three new cases of the Omicron variant found among people who went on a harbor party cruise, sending officials rushing to trace contacts.

Authorities have been easing restrictions in Sydney since early October when the city emerged from a nearly four-month lockdown to contain the Delta coronavirus variant after the population reached higher vaccination levels.

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"We have seen recently increased transmission in larger social venues ... and that is certainly a contributing factor to the increase in cases," Marianne Gale, New South Wales Deputy Chief Health Officer, said in a video posted on Twitter.

Dozens of people who attended a Sydney pub quiz tested positive for the coronavirus and officials are awaiting the results of genomic tests to see if they are infected with the Omicron variant.

Daily COVID-19 infections have been steadily rising as restrictions have eased with New South Wales state, which includes Sydney, logging 420 new cases on Thursday, its biggest rise in about two months, with most caused by the Delta variant.

But the number of Omicron infections has been creeping up since Australia reported its first case about two weeks ago.

Some 50 cases have now been detected including the three linked to the Sydney party boat.

The variant is potentially more contagious than previous ones although initial signs point to a more mild illness. None of the 151 people in hospital in New South Wales for COVID-19 are infected with the Omicron variant.

Australia has fared much better than many countries in containing the pandemic, with nearly 224,000 cases and 2,082 deaths, mostly due to its decision to close borders in March 2020.

But border closures have cut off the flow of skilled migrants causing a sharp slowdown in population growth, prompting businesses to bemoan the lack of workers.

The trend has been worsened by a long-running fall in fertility rates, which hit a record low last year, official data out on Wednesday showed.

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