The Northern Territory has declared all Sydney residents a “threat”, confirming it will keep its borders closed to them for at least another four weeks.

The NT border will now be closed to anyone travelling from Greater Sydney for at least a month, after the state of NSW recorded 17 new cases overnight.

Chief Minister Michael Gunner said the level of community transmission in the New South Wales capital was concerning enough to justify the call.

“For anybody who does come, they know what’s waiting for them – two weeks in a supervised facility and a bill for $2500,” Mr Gunner said.

“The outbreaks of concern are confined to Sydney and appear well-managed, but are still growing. There is still community transmission which means Sydney will present the threat for the foreseeable future.”

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RELATED: Queensland won’t hesitate in closing border with NSW

NSW health authorities warned on Monday that the coming two weeks will be a “critical period” for getting on top of community transmission.

Earlier today, Queensland Premier Annastacia Palaszczuk says she will “slam the borders shut” to New South Wales if widespread community transmission of coronavirus occurs.

As health authorities in NSW monitor various outbreaks of COVID-19, Ms Palaszczuk said she will act on any future health advice regarding the border given her state has just five active cases.

“Every single day we are monitoring what is happening in NSW,” she said.

“We will not hesitate to declare hotspots or if it gets out of control, to slam the border shut.”

RELATED: South Australia to ban anyone in Victoria from crossing into the state

Queensland recorded no new cases of coronavirus in the past 24 hours, she announced, and there are just five active cases in the state.

“Complacency is our enemy,” the Premier warned.

Meanwhile, time is ticking for South Australian residents currently in Victoria to make it back across the border as a new deadline looms.

From Tuesday, a new hard border will apply to anyone – including South Australian residents – to enter the state. Until now, only essential travellers and citizens have been allowed entry from Victoria into South Australia – but now even they will be blocked from entry.