The Victorian government wants a judge to throw out "futile" legal claims for economic loss and mental injury by individuals and businesses during Melbourne's second COVID-19 wave.
Government lawyers told Victoria's Supreme Court on Monday the class actions had no reasonable prospects of success and it would be "futile" to allow them to proceed.
One claim is being led by 5 Boroughs NY Pty Ltd, which owns a New York-inspired restaurant at Keilor Park, for economic loss as a result of Melbourne's 112-day lockdown last year.
Jordan Roberts, made redundant from his job at road barrier company Australian Barriers in August, is heading the separate lawsuit on behalf of individuals for both economic loss and psychiatric injury.
The class action don't argue restrictions shouldn't have been imposed.
Instead, they claim the state's handling of hotel quarantine, which allowed COVID to leak into the community, was negligent and caused foreseeable loss to individuals and businesses.
Acting for the government, Rachel Doyle SC told Justice John Dixon the plaintiffs' legal arguments were incoherent in their reliance on "the end of a long line of dominoes".
Ms Doyle said the class actions simply argued "that led to this led to this led to that" and failed to identify specifics, including the loss claimed.
She argued it was not enough to say "well if this hadn't happened and that hadn't have happened and here we are" and use this to mount a claim for damages.
Victoria's hotel quarantine system was overhauled following a damning judicial inquiry.
The class action applications are due to continue on Tuesday.