South Australia is imposing a raft of new COVID-19 restrictions from midnight, as the state battles an outbreak of the virus.

Gyms, recreation centres, trampoline and play cafes will close, while community sport will be cancelled but outdoor bootcamps can continue.

Gatherings at homes will be restricted to 10 people.

Hospitality venues will be capped at 100, while bookings will be capped at 10. No stand-up drinking will be permitted.

Wedding guests must register their attendance, while funerals have been capped at 50 people. Churches will be capped at 100.

All activities with a COVID management plan in the next fortnight have been cancelled.

Masks will be mandatory for people providing personal care services, such as nail salons and hair dressers, and masks will be encouraged for clients too.

In aged care facilities, masks will also be required when physical distancing is not possible.

Personal care workers will be limited to one site only and visitors will be capped at two per day.

New distancing requirements will also come into effect — including for weddings, churches, funerals, hospitality, personal care services, theatres and cinemas — with one person per 4 sqm.

Schools will remain open.

“It is likely that we will have these directions in place for two weeks,” Premier Steven Marshall told reporters on Monday.

“Of course, if we can remove them early we certainly will.”

People have also been advised to work from home wherever possible and wear a mask when they cannot socially distance, such as while using public transport.

Vulnerable people have been encouraged to stay home and avoid visitors.

“It’s fair to say that we are now facing our biggest test to date, but we can and we must rise to this new challenge,” Mr Marshall said.

“The health expert advice at the moment is very clear — we are to act hard and early, and keep these restrictions in place for a shorter period of time.”

Mr Marshall further announced all incoming international flights had been suspended for the rest of the week.

He also revealed he had accepted help from the Australian Defence Force, which had been offered by the Prime Minister.

“We will throw absolutely everything at this to get on top of the cluster,” he said.

Mr Marshall said the state could not wait to see how bad the spread got before acting.

“The next 24 hours will be critical but we are not going to wait for the situation to deteriorate,” he said.

“Time is now of the essence and we must act swiftly and decisively on the health advice to stay ahead of the game.

“I want to thank the people of South Australia for their patience in waiting to be tested.

“This may seem hugely inconvenient, but testing is absolutely critical.”

Mr Marshall said the state had also boosted its contact tracing team.