Premier Daniel Andrews' stern warning after thousands packed out Melbourne beaches

Premier Daniel Andrews has pleaded for Victorians to not drop their guard after thousands of people flooded Melbourne beaches on Cup Day yesterday.

Crowds packed out St Kilda, Williamstown and Brighton beaches, with minimal social distancing and hundreds of people not wearing masks.

Mr Andrews warned despite the state recording zero new coronavirus cases over five consecutive days, the situation was "fragile".

"We just don't want to see any more scenes of people too close together and people not wearing their masks," he said.

"Make good choices for safety. It's still lurking there, it's still smouldering.

"It is fragile and it will not last if every Victorian doesn't play their part."

Mr Andrews also slammed Freedom Day protesters which led to more than 400 arrests and a female police officer breaking her arm yesterday.

"This is shameful behaviour, absolutely shameful behaviour," he said.

Today's numbers have taken the 14-day rolling average in metropolitan Melbourne to 1.7.

READ MORE: Melbourne's coronavirus home visitation rules explained

In regional Victoria, the average remains at zero.

The state's five-day streak of zero new COVID-19 cases has prompted the borders to reopen with NSW come November 23.

"On Monday, 23 November - the NSW/Victoria border will reopen," NSW Premier Gladys Berejiklian said on Twitter.

"We need to keep moving forward as we live with COVID-19."

There are just 30 active coronavirus cases in Victoria. More than 17,000 COVID-19 tests were undertaken yesterday.

Mr Andrews said the border announcement was "very good news" and proved NSW had confidence in Victoria to keep COVID-19 cases low.

However, he urged Victorians to remain in the state over the summer, to help revive the state's battered economy and regional Victoria's tourism sector.

"This is very good news, not just for those who live close to that border but indeed for all Victorians," he said.

"But again I would urge all Victorians, don't be going to Sydney for Christmas unless you absolutely have to. If you want a summer holiday - we have lots of opportunities here."

The message comes as a $84 million investment to upgrade the state's Werribee Open Range Zoo was announced, which will transform the zoo into a "world class" facility.

Works on the new project will start next week and will include a 1.5km sky safari boasting 360-degree views of Melbourne.