Some 70% of restaurants in South Australia are expected to be closed on Christmas Eve and New Year's Eve because of new holiday penalty rates.
The Restaurant & Catering SA Association said any venues which opened would have to pay 250% penalty rates.
The ABC reports part-day public holidays were declared this year as part of wider changes to retail trading times in the state.
The penalties apply for employees rostered between 7pm-midnight, apart from casuals. Permanent staff also must be given the option of choosing not to work at those times.
Association chief executive Sally Neville said most venues could not afford to open.
"It's going to be quite a challenge for restaurants over this period," she said. "Businesses that are open will be applying a surcharge to their customers."