An eastern Sydney limousine driver's COVID-19 vaccination history and mask use habits are under scrutiny after he came down with the virus and infected at least two other people.
A new health alert, meanwhile, has been issued for a fruit grocer in inner west Sydney's Leichhardt, joining numerous east Sydney venues, as well as the Northmead Bowling Club and stores at the East Village Shopping Centre in Zetland.
The COVID-19 outbreak in Sydney's east on Thursday grew to three cases after a woman in her 70s was exposed to the virus at the Belle Cafe in Vaucluse.
The alarm about the latest outbreak was sounded on Wednesday when NSW Health discovered a man in his 60s and his wife had tested positive for COVID-19.
The Bondi man works as a limo driver transporting international flight crews.
Police are investigating whether he breached any health orders, which require those working around the hotel quarantine system to be tested for the virus daily.
The man was first tested for the virus on June 15, when he returned a positive reading. It's unclear when he began working in the system and only sought COVID-19 testing when his employer requested he do so.
It is also unclear if the man - who has the contagious Delta virus variant - was wearing personal protective equipment as required for frontline workers, or if he had been vaccinated.
Health Minister Brad Hazzard said the fact transmission had occurred outside the man's household was concerning, but NSW's track record on suppressing COVID-19 was reassuring.
"There have been 190,000 people go through the Sydney hotel quarantine system and there's been a handful of issues over that time," Mr Hazzard told ABC radio on Thursday.
"This particular driver was bound by the public health orders which require him to have masks, PPE, when he was picking up international travellers. He was required to have salivary tests each day he was working.
"The system has always relied on policy constructs, trying to encourage people to have the vaccine ... in terms of forcing people to have a vaccine, in any walk of life, it's not been something governments have thought appropriate."
Additionally, a man in his 40s has tested virus-positive in the Baulkham Hills area.
But NSW Chief Health Officer Kerry Chant cautioned this might be a false positive or an old case as the viral load in his system was very low.
Mr Hazzard later said that "on balance" the result was indeed a false positive.
Western Australia and South Australia have nevertheless moved to enact restrictions, shutting the border for those who attended virus exposure sites.
Victoria on Thursday evening took the same step, with residents from the City of Sydney, Waverley and Woollahra council areas obliged to obtain a travel permit, get tested and isolate until they receive a negative result if they cross the Murray.
WA Premier Mark McGowan says authorities are "carefully and closely" monitoring the situation and will reimpose hard border arrangements with NSW if deemed necessary.
The outbreak could also mean NSW reintroduces some restrictions ahead of the school holiday period, which begins on June 26.
NSW Premier Gladys Berejiklian urged everyone to act with caution.
Those catching Sydney public transport are advised to wear masks and extra pop-up testing clinics have been set up in Sydney's east.
"Unless you absolutely have to attend a large gathering, absolutely have to engage in activities of a social nature ... we ask everybody to refrain," she said.
Potential exposure venues include a cinema and shopping centre in Bondi Junction, stores in Castle Hill, cafes in Vaucluse and North Ryde, a car wash in Redfern and stores in Zetland, including at the East Village Shopping Centre.
It also includes the Harris Farm fruit grocer in Leichhardt on Tuesday morning, and Northmead Bowling Club on Sunday afternoon and evening.
They are in addition to public health alerts issued last week for venues in the towns of Moree, Forbes, Dubbo and Coonabarabran.
Australian Associated Press