GPs will only see urgent and emergency cases as they prepare for what could be the “most challenging time faced during the pandemic”.
NHS Shetland said the changes would apply from Wednesday until Friday, 5th January, to free up capacity during the festive period.
Patients are being told to first seek advice from NHS Inform and consider whether other services, such a pharmacist, may be more appropriate.
The health board has stressed, however, that anyone with serious health concerns or symptoms will be able to speak with a GP.
Director of community health and social care Brian Chittick said: “There is no doubt that the next four weeks could be the most challenging we have faced during the pandemic.
“There may be times when patients could be asked to attend appointments in health centres other than the one they are registered at in order to receive a timely appointment.
“Staff are working tremendously hard to keep services running; some are even sacrificing their much needed festive leave.
“I would personally ask that we all treat each other with kindness and compassion, especially at this time of year, and acknowledge that we are all trying to navigate our way through this next wave of Covid infections.”
GPs will be supported by advanced nurse practitioners to ensure patients have access to care and advice.
In evenings and weekends, patients can also speak with NHS 24 on111 which will help decide whether they need to see a GP.
Practice nurses will continue to work as normal, seeing patients for screening, check-ups and reviews.
Any patient who has an appointment with their practice nurse, should still attend.
Patients are also being asked to “flow before you go” by taking a lateral flow device test before attending any health appointment.
Anyone testing positive must book a PCR, start isolating and not attend the appointment.
Patients with symptoms of winter illnesses such as cold, flu and norovirus are also asked not to attend health centres.