THE Department of Health and Human Services (DHHS) have failed to answer questions from a resident who says their daughter became a confirmed COVID-19 case this week without being added to the official figures.

Red Cliffs Secondary College teacher Vikki Arthur became frustrated with reports of just one case in the area, after her 25-year-old daughter was diagnosed with the virus on Monday this week – two days after the first case was confirmed publicly.

The department website still listed the Mildura municipality as having only one confirmed case as of Friday morning.

Ms Arthur's daughter, Harriet, had been working in England until the Department of Foreign Affairs issued a warning for all travelling Australians to return home.

She self-isolated and was confirmed for the virus on Monday this week, having only had contact with her mother.

Ms Arthur said she was notified by DHHS on Friday morning that she had also tested positive.

"I went and picked her up from Adelaide and we drove back together and she hasn't left the house since but I had," Ms Arthur said.

"I tried to ring to organise a test on my way to Adelaide because I wanted to get her in straight away but she hadn't been to the doctor in a while so she wasn't a patient and the whole thing was a bit of a nightmare.

"I was told I was still meant to be going to work which seemed really odd at the time and I only went for two days because she wasn't showing any symptoms."

Ms Arthur said she called the coronavirus hotline a number of times but because her daughter was showing little symptoms and no fever, she wasn't deemed as high risk.

Harriet was then tested, organised through Tristar, on Thursday last week.

"She finally ended up having the test on the Thursday morning last week and I had been to work the Wednesday and Thursday and then Friday her coughing got really bad and so I decided I couldn't go to work and put people at risk," Ms Arthur said.

"The Educations Department at that stage were still saying at that stage that I could go to work – now they have changed it that if you are in contact with someone who has travelled you can't go out.

"On the Monday (this week) she was confirmed."

After Harriet's diagnoses, Ms Arthur also self-isolated until her results were confirmed in a phone call from DHHS.

Ms Arthur is now urging the people of Sunraysia to do everything they can to stop the spread of the virus.

"People need to stay home, that's the end of the story really," she said.

"We were getting some mixed signals from the doctor and health department but I think you just need to stay home.

"Nothing really matters – educations, school and even being a teacher – none of it matters if people are dying.

"Stay home until it's over – they really should have shut this all down before this."

The Department of Health and Human Services was contacted for comment.