Scott Morrison’s plans to get Australia’s internal borders open in time for Christmas may be trashed just days after being announced, with a growing cluster in Adelaide prompting several states to tighten entry rules.

Queensland, Western Australia, the Northern Territory and Tasmania have already thrown up their borders again to South Australia in the face of the outbreak, with the Prime Minister saying he “anticipates” other states might follow.

By Monday morning, the cluster in Adelaide’s north had grown to 17 cases. Most are linked to one family group, and SA Liberal Premier Steven Marshall said his health officials had the outbreak in hand.

But that hasn’t stopped some premiers reinstating quarantine measures and entry restrictions to South Australians heading interstate.

Premier Steven Marshall. Photo: AAP

NSW and Victoria will not follow, keeping their borders open to SA.

But Victorian Premier Daniel Andrews said his government was declaring the state a COVID hotspot and mandating tougher entry requirements.

The border setback comes just three days after almost every member of the national cabinet – except Western Australian Premier Mark McGowan – agreed to the ‘Framework for National Reopening Australia by Christmas‘.

With less than six weeks until Christmas, the hope for most states to have open borders by then might be in peril.

“I anticipate other jurisdictions will make similar decisions [to close borders] and that’s for them to do,” Mr Morrison said on 3AW Radio on Monday.

“These are always temporary measures and they need to be done on the basis of health advice.”

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It is unclear how long the border closures will remain in the various states, but similar COVID restrictions are – as a rule – applied for two or more cycles of the virus’ incubation period of two weeks.

That could mean borders remain shut for at least a month.

It comes despite the national reopening framework saying that state borders should remain open if there are fewer than 50 cases a day nationally.

“Managing a very small number of new COVID‐19 infections is possible,” the framework reads.

Tasmania, the Northern Territory and Queensland closed their borders to SA on Monday, declaring Adelaide a ‘hotspot’. Victoria’s border with the state will stay open, but Adelaide residents must undergo stricter screening and possibly have to take COVID tests before entering Victoria.

Mr Morrison and the federal government have pushed for a more targeted hotspot model on border closures and travel restrictions, arguing entire states shouldn’t be locked out on the basis of an outbreak in one town.

“The whole point of the hotspot is that it does provide that temporary protection,” he said on 3AW.

“It’s important, though, that as Northern Territory has demonstrated, they put areas of the country, not entire states, on hotspots from time to time, and they quickly take them off again.”

NSW Premier Gladys Berejiklian said her state would not close its borders to SA, despite the “concerning” situation, adding “we need to learn to live with COVID”.

“You can’t shut down borders and disrupt lives every time there is an outbreak and disrupt businesses,” she said.

Gladys Berejiklian says NSW isn’t putting the border back up to SA. Photo: AAP

“We need to have confidence, not just in our own system, but the system in other states to be able to get on top of the virus.”

Ms Berejiklian said if the SA situation got worse, and “if the numbers were in hundreds”, the strategy might change.

Federal Health Minister Greg Hunt said the government had offered Australian Defence Force troops to SA, and a national incident centre was being set up.

“If more is required, more will be provided,” Mr Hunt told the ABC on Monday.

“But these are the sorts of challenges that if we trade or engage with the world, if we bring Australians home, we will face, in a world where there’s over half a million cases a day.”

-with AAP