The state of South Australia on Wednesday announced a series of restrictions to reduce mobility in the community to curb the spread of COVID-19.

All schools, except for those servicing children of essential workers and vulnerable children, will be closed from midnight, the police commissioner said. Pubs, cafes, coffee shops and food courts were all told to shut as well.

The move came following a cluster of 22 cases from a hotel used to quarantine travelers from overseas.

The South Australian Premier Steven Marshall says the measures are a needed "circuit breaker" to stay ahead of the virus.