Federal Health Minister Greg Hunt has warned Melbourne's coronavirus outbreak could be replicated in other parts of the country, as the city reverts to a six-week lockdown.
Stay-at-home restrictions will be reapplied across Melbourne from midnight on Wednesday after a record 191 new cases were detected in Victoria on Tuesday.
Mr Hunt said it would be a difficult six weeks for all Melburnians, including families and small businesses.
"It's Victoria now, it could be anyone," the Victorian MP told Sky News on Tuesday.
"We're all going to have to live with this virus for a long while."
He said nobody should offer "false guarantees" the outbreak in the Victorian capital would not spread to other regions or states.
Melbourne residents and people in Mitchell Shire to the city's north will only be allowed to leave home for work, study, essential shopping or to receive or give care.
Victorian Premier Daniel Andrews said people had become complacent as frustration with restrictions set in.
"We have to take this as seriously as we take bushfire. This is binary. It is life and death," he said.
Failings in the state's hotel quarantine regime are the subject of a judicial inquiry after the disease spread as a result of alleged infection control breaches.
Mr Hunt declined to criticise the Victorian government for bungled quarantine arrangements likely to have contributed to the outbreak.
But he did renew his attacks on anti-racism protests that have not been found to be the source of significant infections.
"It was an additional risk in terms of the messaging and the behaviours some took from it as a result," the minister said.
NSW will close its border with Victoria from midnight on Tuesday, with permits to be issued for people who need to travel interstate for work or health care.
Only South Australian residents will be able to enter their state from Victoria and those who do will be forced into 14 days' quarantine.
Victorians granted permission to cross for exceptional circumstances will be made to wear personal protective equipment, including face masks.
Qantas and Jetstar will significantly reduce flights to and from Melbourne until the end of July at least following the border closure.
The Sydney to Melbourne route will be the hardest hit, but will still operate several flights per day, while other routes like Melbourne to Byron Bay will also be affected,
The federal government is supporting border closures despite having railed against earlier interstate travel restrictions, particularly in Queensland.
"This is the first moment where we felt it was appropriate to have border restrictions," Mr Hunt said.
"The risk of community transmission passing between states was, for the first time, live and significant."
Prime Minister Scott Morrison has approved Victoria's request for a further 260 defence force personnel to help Victoria Police with roadblocks around Melbourne's perimeter.
The federal government has also agreed to cap international arrivals to Western Australia at 525 people a week to ease pressure on hotel quarantine.
WA Premier Mark McGowan urged Mr Morrison to reduce the number of arrivals after the system came under strain.
Queensland Premier Annastacia Palaszczuk has also called for a limit on arrivals in her state as pressure mounts for more flights to land in Brisbane.
Australian Associated Press