However, the local health board insists there will be no adverse impact for the most vulnerable patients in the region.
Some hospital operations are expected to be cancelled, along with some doctors appointments, during the national industrial action by members of the British Medical Association tomorrow (Thursday, June 21).
NHS Borders Chief Executive Calum Campbell said: "We expect many of our doctors will support the industrial action, so we have been working in partnership to ensure we can continue to deliver essential services and that there will be no adverse impact for our most vulnerable patients.
"BMA members are working with us to ensure that all emergency and urgent appointments and treatment will take place as usual.
"Some non-emergency will be cancelled to help ensure emergency and urgent work can continue. This means that some planned operations, outpatient and pre-assessment clinics at our hospitals and health centres will be rescheduled. Those patients due to attend a service which has had to be cancelled will be contacted and their appointments will be rescheduled as soon as possible.
"If you have an appointment for 21st June and have not been contacted then you should attend for your appointment.
"All GP Practices in the Borders will be open on Thursday 21st June. Some GPs will be working as normal and some will only be seeing emergencies and patients requiring urgent medical care. All GP Practices will be happy to advise patients about any planned change to services. If patients have any concerns about their care on the day, they are advised to contact their GP practice in the usual way.
"Mental Health and Learning Disability services are unlikely to face major disruption and patients should attend their appointments unless contacted in advance.
"If patients have any other concerns they should contact the relevant health service area directly to discuss."
Industrial action will not risk patient safety, says Dr Chris Richard, consultant in anaesthetics & intensive care at Borders General Hospital.
He said: "Our dispute is essentially about the Government going back on a deal negotiated in good faith only four years ago. At that time, all NHS staff agreed major changes to their Pension Scheme to make it sustainable for the future. We agreed a tiered contribution scheme so that higher earners contributed more to protect lower paid workers. It also meant an increase in pension age for new entrants, and meant that staff - not taxpayers - take on sole responsibility for any further increases needed to cover increases in costs, such as those created by people living longer. Now the government wants to tear up that deal.
"Doctors believe that the changes are unnecessary and unfair. The NHS Pension scheme is not a drain on taxpayers. It currently delivers a surplus of £2 billion to the Treasury each year.
"On the day of action, patients can be assured that doctors in hospitals and general practice will be in their usual workplaces but providing urgent and emergency care only."