NHS Highland is experiencing “extreme systems pressures” due to increasing numbers of staff self-isolating with positive Covid-19 contacts.
The health board issued a public warning after a surge in staff absences in the five days to Tuesday, June 29.
Mental health, primary care, community and acute services are also seeing unprecedented levels of demand.
NHS Highland experienced the highest daily rate of new coronavirus cases this year on June 23, with 122 people testing positive.
Since June 10, the area’s seven-day average has surged from just 9.1 to 90.7 on June 26.
NHS Highlands said all services were reporting very limited capacity with longer than normal waiting times.
A spokesperson for the health board said: “All steps are being taken to manage patients as safely as possible within the Highland system.
“Patients presenting at the emergency departments are being given information on NHS 24 as well as suitable alternatives for care.”
NHS Highland said anyone with a non-life-threatening condition who would usually go to Accident and Emergency should call NHS 24 on 111 first, at any time, to be directed to the right service.
But, if you have a life-threatening emergency such as stroke or bleeding which will not stop then you should call 999.