NHS Highland has warned that some patients with bone and muscle diseases, such as arthritis, might experience delays in receiving care.
The health board said the situation had been caused by an unsuccessful attempt to recruit two full-time rheumatology consultants.
Locum doctors have been hired but NHS Highland said the amount of outpatient clinics would be reduced.
The board said it was hoped the problems would be short term.
It plans to re-advertise the two posts again in July.
Dr John Harvie, consultant rheumatologist for NHS Highland, said efforts would be made to minimise inconvenience to patients.
He said: "We acknowledge that there is increased pressure on the rheumatology services at present.
"In the short-term some patients may notice some delays in being seen or will need to come into Raigmore, but we will make sure nobody's care is compromised.
"Extra clinics are planned, including weekends and evenings and we will do everything we can to ensure a high standard of care."