With Victoria recording no new COVID-19 cases for an eighth day, Premier Daniel Andrews has announced details of workplace returns and an easing of mask rules.

The Brisbane hotel quarantine scare has Victorian health authorities on high alert, even as the state's stalled return to work schedule is cleared to resume.

Victoria has gone eight consecutive days without a new local or interstate coronavirus case and its mask rules will also be relaxed from Monday.

But 18 Victorians who were quarantining in Brisbane and are now back have been asked to isolate and be tested.

There is also ongoing debate about the Australian Open tennis tournament, with the first of the international stars competing set to touch down in Melbourne early Thursday evening on a charter flight.

Premier Daniel Andrews vigorously defended the decision to go ahead with the tournament as thousands of Victorians remain stranded interstate.

He added Sydney's red zone will be reduced as soon as possible so more Victorians can return home.

Brisbane's Grand Chancellor Hotel was shut down this week when six people linked to the quarantine facility tested positive for the highly contagious COVID-19 strain.

Mr Andrews said there were different circumstances for all 18 travellers, who had returned from Queensland since December 30.

He added some will need to isolate and others will only need a negative test.

"Obviously that's a pretty serious set of circumstances ... that highly infectious strain out of the UK is a concern to us," he said.

But the return to work schedule will resume next Monday after being put on hold for a week because of the Black Rock cluster.

Likewise, the masks rules will be eased back to how they were at Christmas.

That means they will only be mandatory in some settings, including supermarkets, large indoor retail areas, public transport, hospitals and airports.

Private workplaces can return to 50 per cent capacity from Monday, while public service offices can return to 25 per cent capacity.

Mr Andrews said many will want to continue to work from home.

"For many people, they're going to want much more flexible working arrangements," he said.

Opposition spokesman Matthew Guy called on the government to also bring back half the public sector to offices.

"The best thing we can do to help small business in the CBD is to bring half our public sector employees back, just as we we're bringing half of the private sector back. That's common sense," he said.

Also on Thursday, the premier rejected criticism that the Open is going ahead despite thousands of Victorians being stranded out-of-state.

He said the Open was only going ahead on public health advice and added it is a massive jobs creator.

"Let's not have the tennis and let's not allow any people who are overseas - let's close the border," he said of critics.

"You know ... 'they've all had a year to get back'.

"That would be safer, logically, but it's not the smart thing or the right thing to do."

He also hopes to make an announcement soon about narrowing which areas in Sydney are red ones under Victoria's permit system.

"I understand it's not easy," he said.

"I just want to assure all Victorians and particularly those that want to come home but can't because it's not safe right now, you will be in this circumstance for not a moment longer than the public health experts tell me you have to be."

Some 16,533 test results were received in the 24 hours to Thursday morning.