One new COVID-19 case in Sydney

Masks will once again be mandatory on public transport in Sydney
Masks will once again be mandatory on public transport in Sydney

A man in his 50s has been diagnosed with COVID-19 after he shopped last weekend at Bondi Junction at the same time as the driver who sparked the latest outbreak in Sydney.

The list of hotspots has now expanded considerably and NSW Premier Gladys Berejiklian says masks will once again be mandatory on public transport in Sydney from 4pm for five days.

"We are strongly recommending that if you are a casual contact that you not travel in the next little while," she told reporters on Friday.

"In relation to mask wearing, we are recommending that if you go to an indoor (Sydney) venue you wear a mask, whether it is a cinema, hospitality or front-line hospitality workers," she said.

The new case comes after the driver and his wife were diagnosed on Wednesday and a woman in her 70s was subsequently infected when she visited the same Vaucluse cafe as the couple.

Another case - a man in his 40s from Sydney's northwest also tested positive for COVID-19 but NSW Health has not yet concluded if it was false positive, but his household contacts have tested negative.

The woman in her 70s and the man in his 40s are included as new cases in the numbers for the 24 hours until 8pm on Thursday. The man in his 50s will be included in numbers released on Saturday.

NSW Chief Health Officer Kerry Chant said the new case that's been diagnosed was a Bondi man who shopped at Myer Bondi Junction on Saturday at the same time as the driver.

He was on the same floor in the same section as the driver and has contracted the same highly infectious Delta strain.

His symptoms began on Tuesday and while infectious he visited venues in Redfern, Newtown, Bondi Junction and Campbelltown and travelled on a train from Newtown to Bondi.

The man's household contacts have tested negative but will now quarantine for 14 days.

Dr Chant said it appeared the driver had passed on the virus with just fleeting contact.

"This indicates that the initial case was highly infectious, as transmission must have occurred through fleeting exposure, noting that the person who caught the infection at the cafe was seated outside and there was no known on-site with the initial case," she said.

The man with the in-doubt case travelled to Canberra on Monday and ACT Health subsequently identified the National Gallery of Australia and a cafe as exposure sites.

The outbreak could mean NSW reintroduces some restrictions ahead of the school holiday period, which begins on June 26.

New Zealand Prime Minister Jacinda Ardern confirmed on Friday that quarantine-free travel will continue with NSW for now.

However, WA and SA have shut the border for those who attended the NSW virus exposure sites.

Victoria also took a similar step, with residents from the City of Sydney, Waverley and Woollahra council areas told to obtain a travel permit, get tested and isolate until they receive a negative result.

Australian Associated Press