A woman in her 70s who travelled from Cuba to London and then on to Perth has become the fourth confirmed case of coronavirus in Western Australia.

The woman, from Perth's western suburbs, visited a range of places between landing in Australia on Thursday and being diagnosed with the virus, including attending a Western Australian Symphony Orchestra concert at the Perth Concert Hall on Saturday night.

The laboratory results returned positive for the virus late on Saturday night, bringing the total number of coronavirus cases to four, WA Health said in a statement on Sunday.

"We are now tracing all of the places and events that she went to so we can publish that information and make sure people are informed," Premier Mark McGowan said on Sunday.

The government is also trying to trace people who may have sat near the woman at the concert so they are informed, Mr McGowan said.

The woman is in a stable condition in self-isolation at home.

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Another woman who travelled to Perth from Jakarta has also been diagnosed with the coronavirus. The woman stayed for several days before travelling on to Melbourne.

Authorities are tracing what the woman did while she was in Western Australia.

WA Health is urging people to stay home and self-isolate if they are undergoing testing for the virus until they get the results.

This can take up to 48 hours.

Besides #COVID19, other respiratory viruses are circulating in WA. If you have any conditions that may ⬆ your risk for a serious viral infection—age 60+, are pregnant, or have medical conditions—call your provider. They may want to evaluate you in person or test you for flu. pic.twitter.com/4HnpnmtZZP — WA Dept. of Health (@WADeptHealth) March 8, 2020

Health Minister Roger Cook said the two cases underscore how important it is for the public to understand that addressing coronavirus is a "community effort".

"If you're being tested for the coronavirus ... you need to exercise some common sense and precaution," Mr Cook said.

"Even if you're a low-risk case, it's important that we all take important steps to ensure that together we can get through this difficult issue."

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Those who have recently travelled overseas and have flu-like symptoms are being urged to call their medical provider to seek advice because of the increase in countries with confirmed cases of the coronavirus, WA Health said in a statement.

"COVID clinics" will open on Tuesday and will be available to people who have travelled from overseas and are experiencing such symptoms, Mr Cook said.

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Mr McGowan said images of people fighting over toilet paper is "frankly disgraceful and not the Australian way".

Two women have been charged after a fight over toilet paper broke out at a Woolworths store in Chullora, NSW, on Saturday morning.

A video of the incident went viral on social media and showed a group of women yelling and fighting over a packet of toilet paper amid panic-buying.

"I just urge West Australians, please don't engage in this sort of behaviour, don't panic-buy, don't do this silly fighting over toilet paper or rice, or whatever it may be," Mr McGowan said.

"All this does is exacerbate an already difficult situation and it's totally and utterly unnecessary."

The wife of James Kwan, 78, who was the first person in Australia to die from the coronavirus, has been released from hospital.

Teresa Kwan is fully recovered and was discharged on Sunday morning, WA Health said in a statement.