Tavistock Minor Injuries Unit (MIU) has closed until at least Saturday due to staff shortages at other Devon medical centres.
It is the latest short-term closure to hit the unit, which also shut for a brief spell over the summer.
A spokesperson from University Hospitals Plymouth NHS Trust told ITV News West Country: "The Tavistock MIU will be temporarily closed due to short-term staff shortages at the Cumberland Urgent Treatment Centre (UTC) and Kingsbridge (MIU).
"Available staff from Tavistock MIU have been redistributed to Cumberland UTC and Kingsbridge MIU."
The closure come at time when the healthcare system in Devon is already under pressure.
The Royal Devon and Exeter (RD&E) Hospital is currently operating at a third over capacity due to high patient numbers, "sustained demand" for Covid beds and ongoing staffing issues.
As a result the county's clinical commissioning group (CCG) has urged people to seek the appropriate treatment.
Chair of the CCG Dr Paul Johnson said: “We really need you to support us.
"Please ask yourself whether you have a genuine life-threatening emergency before attending an emergency department.
"If you are not in the right place, you may be redirected to a more appropriate service. This is because we need to safely prioritise those with the most urgent need.
“We are also asking people to pick up friends or relatives as soon as they are well enough to be discharged from hospital. This frees up beds for other patients who need them.
“Finally, we are seeing high numbers of children coming to hospital. There is a really useful HANDi paediatric app for advice on common childhood illnesses and when to seek help.”