Masks are once again compulsory on Sydney’s public transport after a man in his 50s was diagnosed with COVID-19 after “fleeting” contact with an infected shopper at Bondi Junction last weekend.

“It appears from CCTV cameras that it could have been a very fleeting contact between the infectious person and this gentleman,” Premier Gladys Berejiklian said.

The list of Sydney’s COVID hotspots has expanded considerably and Berejiklian said masks would be mandatory on public transport in Sydney and The Blue Mountains from 4pm on Friday for five days.

“If you are catching public transport, please, it is compulsory,” she told reporters on Friday.

Queensland has declared the Waverley council area in eastern Sydney a coronavirus hotspot and all visitors who have been to the area will have to enter hotel quarantine on arrival.

Residents or people who have visited the Waverley Council area in the past 14 days will be ordered into hotel quarantine on arrival in Queensland from 1am on Saturday.

NSW Health is investigating the possibility of the outbreak stretching into Canberra after a man in his 40s from Sydney’s northwest also tested positive for COVID-19.

It’s possible the case is a false positive because his test results showed low virus levels, he’s not yet linked to any known cases and his three household contacts have all returned negative results.

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

The premier also described the spread of the virus as “scary”.

“Some people for some reason aren’t contagious and some are extremely contagious. The randomness of that is what makes it scary,” she said.

“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 issue of mandatory COVID-19 vaccinations for frontline health and allied workers has been thrown in the spotlight by the cluster of three sparked on Wednesday night when an unvaccinated limousine driver from Sydney’s east and his wife were diagnosed and a woman in her 70s was subsequently infected at a Vaucluse cafe frequented by the couple.

The man from Bondi transports international flight crews and police are investigating if he breached any health orders, which require those working around the hotel quarantine system to be tested for the virus daily and wear personal protective equipment.

NSW Health Minister Brad Hazzard said there was an expectation but not an obligation for people working on the COVID-19 frontline to be vaccinated.

“There has been a reluctance through national cabinet to have mandatory testing,” he told ABC television on Thursday.

“But it’s certainly something which … we’re now looking very closely at.

“So, I’ve asked our lawyers to give us advice on that. And we’ll be making some decisions shortly,” he said.

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.

Sydney’s 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 in Leichhardt and Northmead Bowling Club on Sunday afternoon and evening.

People at those venues at that time should get tested, self-isolate and wait for further advice.