COVID-19: New coronavirus cluster emerges in Berala, western Sydney

A cluster of new coronavirus cases has emerged in New South Wales, health officials said on Sunday, just as Australia appeared on the verge of snuffing out community transmission.

Health authorities have been investigating a mystery case in a man who tested positive on Friday in Berala, a suburb of western Sydney. All six locally acquired cases registered on Sunday were close contacts of the man.

Last week Australia, which has managed the coronavirus better than many other nations through targeted lockdowns and high rates of testing and contact tracing, recorded a day of zero locally acquired cases - raising hopes that outbreaks in three states over the summer holidays had been brought under control.

The latest outbreak shows how easily the virus can spread, New South Wales state leader Gladys Berejiklian told reporters in Sydney, as she called for more people to come forward for testing.

"What is really important is to make sure that, given we are towards the tail end of this particular outbreak, that there have not been other superseding events and we want to keep it that way," Berejiklian said.

Australia has a strict policy of two weeks in hotel quarantine for returned international travellers.

The country has tightened procedures since the virus seeped into the community from a hotel security worker last May, sparking a second wave and a four month lockdown in the second biggest city of Melbourne.

On Friday, three people on two charter flights tested positive on arrival in Melbourne, which will host the Australian Open tennis tournament next month, and among the people placed in hard hotel quarantine were 47 players, who are barred from leaving their rooms to practise.

Australian Open tournament director Craig Tiley on Sunday confirmed the year's first Grand Slam will go ahead from Feb. 8 despite anger from some of the players over the quarantine rule.

Australia's new infections rose to 18, of which 12 involved returned travellers, health officials said, bringing the country's total to just over 28,700 cases and 909 deaths.