Announcing the seven-day lockdown extension on Tuesday, Premier Daniel Andrews made it clear the decision was informed by a real-time worst case scenario.

“We need to avoid what is going on in Sydney at the moment, and we are determined to do that,” he said.

When asked about reports on Sydney receiving first a large share of a newly arrived batch of Pfizer vaccine doses, Mr Andrews steered away from responding whether he considered it “unfair”.

He instead reiterated the situation is “different” there. “We wish them well,” he said.

“As soon as they (NSW) get it under control, it takes a lot of pressure off us and Adelaide and Brisbane and the whole country.”

READ MORE: South Australia goes into lockdown: Greek restaurant listed as exposure site

Victorians woke up to 13 new locally transmitted coronavirus cases on the day the snap lockdown was due to expire.

They include one mystery case of a Roxburgh Park woman in her 20s, with COVID-19 response commander Jeroen Weimar confirming there were virus fragments detected in the City of Hume suburb.

The stubborn double digit daily tallies over the past week was deemed a key indicator by authorities they need more time to suppress the current Delta outbreak.

As was the rise and spread in close contacts – with more than 18,000 identified – and exposure sites which have surpassed 300, across the state.

“We have seen significant and stand-alone outbreaks in regional areas in Phillip Island, in Bacchus Marsh, Barwon Heads and as far away as Mildura,” Victoria’s CHO Brett Sutton said.

“Around a third of all of our primary close contacts are right across regional Victoria.”

But Prof Sutton stated hopeful that by next week there won’t be new cases popping up that have been infectious in the community.

A two-week pause of Red Zone Permits for Victorians returning from New South Wales was also announced. From 11.59 pm Tuesday 20 July, any resident returning after midnight will require an exemption to enter the state.

“They’re not locked into Sydney, so they must be locked out of Victoria. That’s the choice I’ve had to make,” Mr Andrews said.

In a statement, he cited Delta’s high transmission rate as proof that a further incursion of cases from interstate “would potentially cause the lockdown to last even longer.”

Suggestions that NSW’s responsibility extends beyond their borders were brought back by Mr Andrews when asked about the way ahead for Victoria.

Replying to whether measures other than lockdowns were being considered as a response to future outbreaks, he said it depended on the neighbouring state’s own virus spread and any restrictions they would have in place to prevent incursions.

“I remind you that the ring of steel we had in Melbourne last year didn’t just protect country Victoria. It protected the whole country,” Mr Andrews said.