The Northern Territory is beefing up its borders to lock out travellers from coronavirus hotspots.
Chief Minister Michael Gunner says the ban on Victoria and Greater Sydney could be in place for more than a year.
"We will have hard border controls in place for at least the next 18 months," he told the ABC on Tuesday.
Mr Gunner said extra police and health officials are being recruited to help monitor arrivals into the NT.
The Territory reopened its borders on 17 July to everyone except those coming from a coronavirus hotspot.
Mr Gunner says the NT is "much more likely to add [hot]spots than remove them" and urged residents to stay within the Territory.
"We have a definite ban on Victoria and Sydney keeps bubbling away and I can't see a view when that would lift. My advice to every Territorian is - if you can, stay here in the Territory. You're safe here, don't go," he said.
"If you can, cancel your Christmas holiday plans."
The Territory has only recorded 34 COVID-19 cases, three of which are active.
The tough-on-borders pledge comes amid a tight Top End election, with voting already underway.
Mr Gunner has been accused of politicising the COVID-19 crisis in a bid to retain government for Territory Labor.
People in Australia must stay at least 1.5 metres away from others. Check your state’s restrictions on gathering limits.
If you are experiencing cold or flu symptoms, stay home and arrange a test by calling your doctor or contact the Coronavirus Health Information Hotline on 1800 020 080.
Additional reporting by Evan Young.