There are fines for breaking Australia's national large gatherings ban dring the COVID-19 pandemic

Crikey Worm, 16 March 2020:

EVERYTHING WILL BE FINED

State governments and police will take responsibility for enforcing penalties over the new quarantine rules, with Morrison encouraging a “dob in” your mate system, and Pedestrian.TV reporting that, under existing rules, fines for breaching public health orders carry wildly different penalties according to state.

• Victoria: $6,400
• Tasmania: $8,400
• Queensland: $13,345
• South Australia: $25,000
• NSW: $11,000 and six months’ jail
• WA: $50,000 and 12 months’ jail

The Sydney Morning Herald and the ABC respectively report both NSW and Western Australia police will enforce the existing laws; ditto Queensland police, who will conduct random check-ins.

South Australia, meanwhile, has officially declared a public health emergency, the ABC reports.