South Australian pharmacies appear to have sold out of face masks as SA Health reveals it is testing three more people in the state for coronavirus.

Key points: Seven South Australians have been tested for coronavirus

Seven South Australians have been tested for coronavirus Face masks have sold out in pharmacies statewide

Face masks have sold out in pharmacies statewide SA Health says it has a face mask stockpile in case of an epidemic

A total of seven South Australians have now been tested for the disease, which has killed more than 100 people in China.

Three people have been tested this week, on top of four last week.

One of last week's tests has come back negative, while the others are still being examined in Victoria.

SA Health believes the likelihood that these people have contracted the disease is low.

Chief public health officer Nicola Spurrier said the patients self-presented with symptoms and quarantined themselves.

She said there had not been any confirmed cases of coronavirus in South Australia.

"It's people that have travelled in mainland China, and have developed some respiratory symptoms and particularly a fever since returning to Australia," Dr Spurrier said.

"We're quite comfortable that these patients, people presenting, are at relatively low risk.

"Also, I think it's important to say that while we're waiting for these tests to come back, these people are keeping themselves isolated so are not causing any further option for spreading."

She said people who had been to China and had flu-like symptoms should contact their GP to get tested.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 54 seconds 54 s Health Minister Greg Hunt and chief medical officer Brendan Murphy urge doctors to wear face masks.

Pharmacies sold out of face masks

Pharmacies from across Adelaide have told ABC News they have sold out of face masks.

Each time they refilled their stocks, they sold out again, they said, with demand continuing to increase.

Social media users have also complained about face masks being unavailable at both pharmacies and hardware stores.

Eduard Gjergji said he went to Priceline Pharmacy at Glenelg, Chemist Warehouse at Clovelly Park and National Pharmacies at Brighton, but all of them said none of their chains had any stock statewide.

"It's very unsafe to be in a first-world country and have no medical masks across the state — it's very concerning," he said.

He and his partner are planning to travel to Europe soon via Singapore and Turkey, and are worried about catching the coronavirus along the way.

"You always could come across someone else sitting at your seat or toilet or anywhere, so we were actually thinking of cancelling, but maybe we'll go ahead with it," he said.

"Safety is the first priority, but it is still concerning you can't have any masks across the whole state. I can't express the concern."

The Federal Government has told doctors and GP surgery staff to wear face masks when seeing potential coronavirus cases and it will dip into the national mask stockpile to make sure there are enough to go around.

Chemist Warehouse in the Sydney suburbs of Haymarket is one of many stores with no stock left. ( Supplied: Reddit )

Stockpile of masks in case of epidemic

Dr Spurrier said SA Health had a stockpile of masks in case of an epidemic.

"If we did need them in a wider community-based way, we would be able to have access to those masks," she said.

"People will also recall that many community members were needing to have masks during our bushfires recently.

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"This wasn't particularly the case in South Australia because our air quality remained relatively good, so in South Australia I'm quite confident we do have the masks and an adequate supply if need be."

SA Health says children who have visited China and particularly Hubei province are able to return to school unless they have close contact with a confirmed case of coronavirus, or show symptoms of the illness.

South Australian Education Minister John Gardner said schools were being made aware of measures they could take to prevent illnesses spreading.

"We're obviously paying close attention and will be listening to advice from the public health officers and providing support and advice to our school as information becomes available," he said.

"We're very fortunate in SA that this hasn't hit us and hopefully SA will stay clear in that way."

Anyone with concerns has been asked to contact SA Health's Communicable Disease Control Branch on 1300 232 272.