Australia's arts sector is being "smashed" by coronavirus and needs urgent financial support, SA Greens senator Sarah Hanson-Young says.

Key points: The arts industry is among the many sectors battling a major downturn

The arts industry is among the many sectors battling a major downturn The SA Treasurer has foreshadowed a major hit to GST revenues

The SA Treasurer has foreshadowed a major hit to GST revenues Coronavirus has forced the cancellation of the Anzac march and the closure of some schools

Concerts are being cancelled across the country, with the Adelaide Festival Centre among the latest venues to announce it will close to the public and suspend performances in the immediate future.

"We deeply regret any inconvenience caused to our patrons and any distress to performers and the teams of people who work so hard to create and produce our shows," artistic director Douglas Gautier said this morning.

"Our thoughts are with those in the arts and creative industries who will be most affected by this challenging situation."

After cancelling shows over the weekend, the Adelaide Symphony Orchestra has also postponed an upcoming concert with Ben Folds, while other performances will be livestreamed.

Greens Senator Sarah Hanson-Young said the sector was in desperate need of stimulus.

"Over 600,000 Australians are employed in the creative and arts sector and the industry contributes $112 billion to our economy," she tweeted.

"The industry is being smashed by coronavirus and needs proper support."

An upcoming concert featuring the music of Ben Folds has been postponed.

Coronavirus is already having huge economic impacts, slashing the value of stocks — with Wall Street suffering its biggest drop in 33 years.

SA's Treasurer Rob Lucas said a significant cut to GST share alongside the bushfires and coronavirus crises means there will be no budget surplus for the next two years.

Mr Lucas said a decision by the independent Commonwealth Grants Commission would slash the state's share of GST by $2 billion over the four-year forward estimates.

"There's now no prospect of a budget surplus this year or indeed next year," he said.

"The reality is our priority is going to be on combating the coronavirus and the recovery from the bushfires.

"It will mean for this year and next year at the least, we'll have to go into a budget deficit for a period of time."

Mr Lucas said further GST cuts are likely when the federal budget is drawn up.

Anzac Day march cancelled

South Australia is now in step with other states over Anzac Day arrangements, with the main march and memorial service in Adelaide cancelled because of coronavirus concerns.

The state's RSL branch said the "decision wasn't taken lightly", but follows similar moves in NSW, Queensland, Victoria, Tasmania and Western Australia.

The main Anzac march in Adelaide has been cancelled. ( ABC News: Dean Faulkner )

Adelaide's dawn service is currently expected to proceed, but it will not be open to the general public and the RSL said it was still working out live streaming arrangements.

However it said plans could change in line with government advice.

The televised march through Adelaide and the service at the Cross of Sacrifice, as well as a youth vigil the night before, will not go ahead.

"They've all been cancelled because they're predominantly public events," RSL SA chief executive David Grenvold said.

"This is one of the most significant days on the Australian calendar, hence the reservations around cancelling this.

"Public safety's obviously paramount. The cohort that attend these — there are some vulnerable members of the community in there, so we've got to do the right thing by them."

Mr Grenvold said the decision had been made after consultation with the SA Government.

"Some agree with the measures, some think it's a little bit over the top. We'll let individuals form their own opinions," Mr Grenvold said.

The RSL said individual sub-branches could hold their own services, which would be limited to members only.

"For 2020, there will be no public access to the dawn services which will occur. This is a decision made with great regret, we know that this is a very solemn and important commemoration," SA Premier Steven Marshall said.

This morning Mr Marshall announced the latest first rapid testing and assessment clinic for coronavirus outside the metropolitan area was opening in Mount Barker.

It follows the creation of similar facilities at the Royal Adelaide, Lyell McEwin, Flinders, Repatriation and Women's and Children's hospitals.

SA Health sticks by plan to keep schools open

The number of coronavirus cases in South Australia yesterday jumped by 50 per cent from 20 to 30, including a teacher at Unley High School and a student at Scotch College.

Both schools will remain closed today.

"[Unley High] will not be operational again until public health officials indicate that it is safe to do so," the Department for Education said.

Drive-through coronavirus testing has started in SA. ( ABC News: Haidarr Jones )

Federal and state authorities are currently sticking by advice to keep schools open.

"It's [a question] on everyone's minds, not only in the state but also the national committees who are looking at this very carefully," SA Health acting chief medical officer Michael Cusack told ABC Radio Adelaide.

Dr Cusack said SA Health was currently "advocating schools to stay open and advocating for parents to send their children to school".

"The information we have from the largest review of COVID-19, which has taken place in China, was that although children undoubtedly will get the infection, they did not find evidence of that infection occurring inside the schools," he said.

"It wasn't the case that children were infecting each other at school. It was much more the case they were getting the infection in their own families.

"From the public health perspective, if we close our schools then obviously the children will need to be cared for and pretty commonly that'll be with grandparents and older relatives.

"If children have the disease, we're exposing perhaps the more vulnerable members of our population to COVID-19."

Dr Cusack said current evidence suggested that anyone who had contracted coronavirus could not then get it again in the short term.

"Based on what we're seeing [about] people's antibody levels after they've had an infection and the way that they rise, we certainly don't think they can get infected again … in the space of two or three months," he said.

"Clearly as we learn more about the virus and as time goes by, we'll be able to give a better sense of whether you can become infected many months down the line."