Indoor mask rules and restrictions on private gatherings are back in Victoria as of Thursday after a man working in Australian Open hotel quarantine contracted COVID-19.

Hundreds of tennis players and their support staff must isolate, and warm-up matches have been suspended, while contact-tracers look for anyone the 26-year-old from suburban Noble Park man might have infected.

The worker visited various places in Melbourne’s south-east while potentially infectious in recent days – including a golf driving range, a Bunnings, two Kmarts, and a cafe.

It’s possible he is sick with the British strain of the virus but authorities won’t know for sure until the return of results of genomic tests, expected on Friday. That strain is known to spread more rapidly.

Premier Daniel Andrews held a late-night media conference on Wednesday to announce the return of rules “out of an abundance of caution”.

“This is one case. There’s no need for people to panic. There’s no need for people to be alarmed,” Mr Andrews said.

“We are all well trained and well schooled in what to do as a state.”

• The Victorian government will update possible exposure sites throughout Thursday. Click here to see them.

The Premier said it was not known how the worker, who is also a CFA volunteer, had contracted the virus.

Mr Andrews said the man had returned negative test results while working in quarantine at the Grand Hyatt in Melbourne’s CBD.

“We can’t particularly determine how it is the person became infected, given that they produced negative test results,” he said.

“All of that will become clearer with a combination of CCTV footage, genomic sequencing, further testing – all of that coronavirus detective work that already well and truly underway.”

Victoria’s testing commander Jeroen Weimar said the man had given “outstanding” information to contact tracers.

About 500 Australian Open players, officials and support crews who were staying at the Grand Hyatt hotel are considered “casual contacts” and have been told to isolate and get tested.

Other hotel workers are considered “primary close contacts” and must immediately isolate, get tested and remain isolated for 14 days.

The man worked his last shift at the hotel on January 29.

He had a negative test at the end of the shift. Later, after he developed symptoms, he got tested and was found to be positive on Wednesday night.

The worker has been transferred to a health hotel.

A Hotel Quarantine worker at the Grand Hyatt Hotel has tested positive to coronavirus (COVID-19).

Anyone who has visited these exposure sites during the times below must immediately isolate, get a coronavirus (COVID-19) test, and remain isolated for 14 days. pic.twitter.com/BNpSOEcpHY

— Victorian Department of Health (@VicGovDH) February 3, 2021

Rules return, caps for workplaces

Mr Andrews said Victoria would return to mandatory masks indoors from Thursday.

“We’re assuming the worst. I think that’s always a smart thing to do,” he said.

Private gatherings have also been reduced from 30 people to 15.

A plan to have up to 75 per cent of workers back in the office from Monday has been paused.

Australian Open organisers confirmed warm-up matches scheduled for Thursday had been suspended. The tournament is still scheduled to run.

We will work with everyone involved to facilitate testing as quickly as possible.
 
There will be no matches at Melbourne Park on Thursday. An update on the schedule for Friday will be announced later today. #AusOpen

— #AusOpen (@AustralianOpen) February 3, 2021

Perplexing mystery

“We are continuing to talk to him tonight to extract as much information as possible about his movements, to ensure we have an accurate view about his contacts and his exposure sites,” Mr Weimar said.

The latest infections come after Victoria chalked up 28 COVID-free days and just hours after the more infectious B117 coronavirus variant, first detected in Britain, spread between two groups of returned travellers at Melbourne’s Park Royal Hotel.

Victoria Police Minister Lisa Neville. Photo: AAP

Victoria’s Police Minister Lisa Neville said genomics had shown those infections were identical.

“That means it’s as if they have been in the same room together,” Ms Neville said earlier on Wednesday.

One of the groups, a family of five who all have the virus, arrived from Nigeria on January 20 and tested positive four days later.

A fellow returned traveller in the opposite room, who restarted her 14-day quarantine stint after her husband arrived on January 16, twice tested negative before returning a positive result on January 28.

Questions remain over how the woman in her 60s became infected, given her partner’s day three and 11 swabs were negative.

-with wires