The Victorian government will deliver an unprecedented $23.3 billion budget deficit next financial year, with net debt expected to blow out to $155 billion within three years, after the state's tax revenue fell by 11.9 per cent.

The coronavirus and the state's extended lockdown have smashed the economy causing employment to fall by 182,800 jobs between the March and September quarters, while economic output is forecast to fall by 4 per cent next financial year.