Visiting has been suspended at Galloway Community Hospital after a rise in the number of Covid-19 infections.
NHS Dumfries and Galloway says coronavirus cases have been traced to a number of different settings in Stranraer.
The health board is carrying out increased testing in the area over the weekend with a mobile unit.
Valerie White, Interim Director of Public Health, said: “I am aware that the decisions regarding visiting will cause a level of anxiety and disappointment among hospital patients, their families, care home residents and their loved ones.
"However, we must ensure that we do everything we can to protect our patients at the Galloway Community Hospital, our Care Home residents, staff and their families as we continue to address the challenges that COVID-19 presents.
“To help investigate this increase in cases, we will increase testing availability to members of the public via mobile testing units over the coming days.
"Our local Test and Protect team will continue to work with positive cases, identify their close contacts and provide relevant advice and support regarding self isolation to prevent further transmission to the community.”
Testing will be available from Saturday to Tuesday 11 am to 4 pm at Ashwood House, Stranraer, DG9 7JJ. If possible, people should pre-register for a test, but testing will also be available for those who turn up on site without pre-registration.
Appointments via the mobile testing unit can be made each day from 9.30 am by logging on to the website:
Anyone who is concerned about symptoms can get advice through the www.nhsinform.scot/ website or by phoning NHS-111.