Western District Health Service chief executive Rohan Fitzgerald said the COVID-19 case was detected after testing at its drive-thru clinic on Wednesday afternoon.

"The patient was in transit to an interstate destination and was screened, then tested at our drive-thru clinic," he said.

"They did not enter Hamilton Base Hospital."

He said nurses followed strict infection control guidelines and wear appropriate protective equipment to eliminate the prospect of spreading the infection.

All people who are tested for COVID-19 are advised that they must home isolate until they receive their test results.

If they have a positive result, home isolation continues until they are cleared by the Department of Health and Human Services, the hospital said.

The department allocates a case worker to monitor the person's medical and social situation on a daily basis.

The person's nominated GP is also informed so they can manage the patient's medical needs.

At this stage confirmed cases are only admitted to hospital if their condition deteriorates and they require more advanced care, the hospital said in a statement.

The department also manages the process of tracing any community contact the person may have had, while symptomatic, it said.

"I understand that a positive result in our community may heighten anxiety, but want to reassure everyone that WDHS is doing everything it can to ensure the safety of residents, clients, patients and staff during this time," Mr Fitzgerald said.

"This case demonstrates the effectiveness of the drive-thru clinic and other social distancing measures WDHS has in place, in reducing the potential risk of transmission of the virus in our facilities.

"WDHS has also introduced strict visitor restrictions to protect staff and those most vulnerable in our aged-care facilities and hospital.

"We understand that limiting access to friends and loved ones in our facilities will cause concern for some members of our community, however, social distancing measures are seen as the best defence in delaying the spread of the virus," he said.

Group activities and some group clinics have been cancelled.

With the first confirmed case, this is timely reminder that all people should be implementing their plans to limit their exposure to COVID19, the hospital said.

"These measures may include self-isolating at home, social distancing and increased hand washing with soap and water and coughing into elbows.

"We all have a role to play in responding to COVID-19 as parents, family members, friends and local businesses, organisations and community groups. Please stay informed and follow the government's recommended guidelines for keeping yourself and others safe.

"In the meantime, WDHS will continue to focus its efforts on preparing our service for the forecast difficult months ahead."

Warrnambool Base Hospital confirmed on Friday that it was not treating any confirmed cases of the virus.

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