Business leaders predict Victoria’s seven-day lockdown will cost more than $1 billion and slammed the lack of federal and state financial support, warning that without a safety net the state was exposed to more job losses and company closures.

Tourism and major sporting codes were thrown into chaos on Thursday as state borders were slammed closed. Travellers were forced to abandon plans to flee Melbourne’s winter, with Qantas, Jetstar and Virgin all cancelling flights in and out of Melbourne.