Victoria had a further 270 newly confirmed cases of coronavirus in the state in the 24 hours to Tuesday morning.

Of the new cases in Victoria, 28 are linked to known outbreaks while a further 242 are under investigation.

There are now 1803 active cases in the state. Of those 81 are in hospital, an increase of 13 from the day before.

Almost 22,000 tests were conducted on Monday.

Meanwhile, South Australia has moved to delay the lifting of border restrictions with the ACT and NSW amid concerns over the rise in COVID-19 cases in Sydney.

Premier Steven Marshall says the state's transition committee has met and decided not to go ahead with the lifting of quarantine measures on July 20.

He says of particular concern is the "super spreader" event associated with the hotel at Casula, in southwestern Sydney, with many people now in isolation.

The NSW government will introduce stricter operating rules for pubs after more than 20 COVID-19 cases were linked to an outbreak at a Sydney pub.

The new COVID-19 rules for pubs and hotels will be announced on Tuesday, including a limit of 300 people regardless of size and group bookings capped at 10 people.

The measures are also expected to include stricter requirements for venues to take contact details of patrons and tougher regulations on pub cleaning.

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Victoria's chief health officer, Brett Sutton, said his state hadn't turned a corner yet in fighting the virus despite the lockdown measures, warning of increased hospitalisations.

"The next fortnight will see a couple of hundred individuals require hospitalisations," he said.

"There's often 10 to 20 per cent of all coronavirus infections who require hospitalisation."

Victorian Premier Daniel Andrews said staff from some of Australia's biggest banks would be trained to assist with the public health effort, should the situation worsen further in the state.

Bank staff will be trained alongside employees from Telstra, Jetstar, Qantas and Medibank to help health authorities.

"We're quite confident that we'll have a number of staff come across to support all manner of different functions in our public health response," Mr Andrews said.

"[The staff are] not to use right now, but in the event for either fatigue management or if the task continues to grow, for them to be potentially deployed in some weeks' time. That's just good forward planning."

A further 1000 Australian Defence Force personnel will also be deployed to Victoria, following talks between Mr Andrews and Prime Minister Scott Morrison.

The extra members will be deployed in the next three to four weeks, adding to the more than 300 personnel on the ground.

Ambulances in the state will now be staffed by one paramedic along with one defence force member, in anticipation of paramedics or hospital staff having to self-isolate or go into quarantine as the virus spreads.

Mr Andrews described the coronavirus in as a "wicked enemy and wildly infectious", warning of a worsening situation should people in virus hotspots breaching lockdown orders.

"Please moderate your behaviour and do the right thing. Otherwise, this strategy simply won't work and we will see tragedy, but we'll also see lockdowns that have to run longer than they should," he said.

"We will see a longer second wave than would otherwise be the case."

The Victorian Premier said further restrictions in the state were on the table.

"We can't rule anything out if there aren't sufficient mechanisms to drive down transmission," he said.

Victorian health authorities also on Monday confirmed two residents had tested positive in the southern state after recently travelling to Merimbula on the southern NSW coast.

NSW Premier Gladys Berejiklian reiterated that life would not return to "normal" until a vaccine is secured and refused to rule out tightening restrictions further.

"In a pandemic, many people indoors is a much higher risk than many people outdoors in a seated venue," Ms Berejiklian told 2GB radio on Tuesday.

"It's not necessarily the numbers - it's what they're doing and how they're doing it. Even five or six people mingling around the bar at a hotel is a huge no-no."

Ms Berejiklian said she also wanted to see pub and hotel patrons restricted to seated service, banned from use of cutlery stations and forced to socially distance in queues.

NSW Health on Monday said 10 coronavirus cases were now directly linked to the Crossroads Hotel at Casula in southwest Sydney while 11 cases were indirectly connected.

NSW Chief Health Officer Dr Kerry Chant later on Monday confirmed an additional eight cases had been reported up to midday - all linked to the Crossroads Hotel.

All patrons of the pub who entered from July 3 to 10 must self-isolate and are being urged to get tested as a precaution. Investigations are ongoing to determine the source of the infection, with further test results expected this week.

Police are working with Liquor and Gaming to investigate if the hotel breached any guidelines.

One of the eight cases initially reported on Monday that was linked to the venue tested positive after also visiting The Star in Sydney on July 4.

with AAP