Gatherings of more than 10 people have been banned and on-the-spot fines have been introduced in South Australia, where the total number of coronavirus cases has risen to 287.

Key points: SA Police Commissioner Grant Stevens announced the new rules on Friday night

SA Police Commissioner Grant Stevens announced the new rules on Friday night SA Health today said there were now 287 confirmed cases of COVID-19 in the state

SA Health today said there were now 287 confirmed cases of COVID-19 in the state A south-east school was shut yesterday after a student tested positive for coronavirus

In addition, South Australian Police last night said gatherings of 10 people or fewer would now be restricted to one person per 4 square metres.

SA Health this afternoon announced there were 30 new cases of coronavirus in the state, with four cases of community transmission suspected.

South Australia's chief public health officer Nicola Spurrier said eight of the new cases were linked to the Ruby Princess cruise ship.

She said one patient had left the intensive care unit (ICU) at the Royal Adelaide Hospital, with five people still there, three of them in a critical condition.

SA Health is also investigating the movements of a Swiss tour group that visited the Upstairs at Hollick restaurant in Penola on March 15.

Anyone who visited the Harvest Kitchen at Calabria Family Wines Barossa Valley on March 14 and the Barn Steakhouse at Mount Gambier on March 15 have also been asked to self-isolate and seek testing if symptoms develop.

Today's new cases range in age from 19 to 79.

SA Pathology has tested nearly 25,000 people so far.

On Saturday morning, Premier Steven Marshall said from today individuals who failed to follow orders to self-isolate would be hit with a $1,000 fine, while businesses "flouting laws" to control the pandemic would cop a $5,000 fine.

"We are only as strong as our weakest link," he said.

"Everyone needs to understand that from today failure to follow the directions to the letter of the law will leave individuals and businesses liable for significant on-the-spot fines.

"SA Police have established a new team dedicated to enforcing quarantine rules, social distancing restrictions and business closure rules, and will be knocking on the doors of individuals and businesses to ensure pandemic restrictions are being adhered to."

Under the new measures, a person who owns, controls or operates a place in the state "must not allow" a prohibited gathering to occur and a person must not organise a gathering of more than 10 people.

Police also said a person present at a gathering, prohibited or not, must "use their best endeavours" to comply with the social distancing rules.

Some gatherings are not included under the new measures, including transiting through malls, gatherings at airports, on public transport, at supermarkets, schools or in Parliament.

'There are some people who are not complying'

SA Police Commissioner Grant Stevens said fines would primarily relate to people who were required to self-quarantine or self-isolate and breached those requirements.

Commissioner Stevens said some individuals were still not following the restrictions. ( ABC News: Nick Harmsen )

"There are opportunities for us to explore whether the issue of an expiation notice is appropriate in circumstances where we have directed that groups of no more than 10 meet," he said.

"But the principle objective here is to ensure that people required to self-quarantine, people who we believe present a risk of spreading the infection, comply with those obligations."

He said people who did not comply with public health orders would face consequences.

"We've seen a growing level of understanding about the seriousness of these restrictions and why they're being implemented," he said.

"But having said that, we do know there are some people who are not complying.

"The ability to issue an expiation notice on-the-spot, I think, sends a very strong and quick message, and I think it will send messages throughout the community that this is being taken seriously."

Large crowds of people have been seen gathering at beaches throughout the country, despite social distancing rules being put in place.

Yesterday, large crowds were spotted at St Kilda beach in Melbourne while last week, Bondi Beach in New South Wales also drew big crowds, resulting in it being shut.

Crowds have been gathering at beaches around the country, despite the plea for people to stay home. ( ABC News: Victoria Pengilley )

Australians returning from overseas will also now be forced to quarantine in hotels for two weeks under supervision across the country.

The Premier yesterday said it would help give the state time to strengthen its response.

"The reality is what we've got to do is put restrictions in place so that we can reduce that peak, push it as far into the future as possible, build up our medical resources and capacity so that we can handle the volume that is likely to come our way," he said.

Student tests positive at south-east school

Earlier this week, it was confirmed that a student at Kingston Community School, in South Australia's south-east, had been diagnosed with coronavirus.

"Parents/carers are currently being contacted," a statement from the Department for Education said.

"Public health officials are carrying out contact tracing and the Department for Education and SA Health will inform anyone who needs to self-isolate."

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The department said the school would be "thoroughly" cleaned to prevent transmission of the virus and the school would not reopen until public health officials declare it safe.

Yesterday, it was also announced that community breast cancer screening services had been suspended for at least three months in the state.

BreastScreen SA said it had made the "difficult decision" to close metropolitan screening clinics and mobile units as a precaution, to protect clients and staff.