Code black situation at Raigmore Hospital with coronavirus pressures
The healthboard say several staff are self-isolating, adding to the strain on resources.
All non-urgent surgery at Raigmore Hospital has been cancelled as it comes under pressure amid an increase in Covid cases.
NHS Highland said the Inverness facility has reached capacity and has been placed at "code black status".
The healthboard said the number of coronavirus cases across the area has now increased "significantly" bringing about an impact on services as some patients are now being admitted to hospitals.
NHS Highland said that a large number of staff are now having to self-isolate as well, which is placing pressure on staffing levels, while over the past week the healthboard has continued to see "unprecedented" levels of demand across health and social care services.
NHS Highland said: "The impact of this at Raigmore Hospital, in particular, has been significant over the past few days. We have reached capacity in the hospital, we have long waits in our Emergency Department and we know people requiring urgent care will still need to come in for treatment. As a result, the hospital is currently at code black status.
"Urgent work is taking place to ensure we can treat our patients appropriately and compassionately.
"We are doing all we can to safeguard services" - Dr Boyd Peters, NHS Highland
"Medical, surgical and clinical support teams are meeting regularly to agree the actions that must be taken and discuss what more can be done to reduce the pressure on services within the hospital."
All non-urgent elective surgery has been cancelled as has outpatient activity, bar cancer care.
The healthboard said that cancer and urgent cases will continue to be treated and staff will also, where possible, carry on with orthopaedic and day case work.
Dr Boyd Peters, medical director for NHS Highland, said: "We are doing all we can to safeguard services but we have had to make the difficult decision to cancel non-urgent work which I know many will find upsetting and frustrating. We are very sorry that we have had to do this.
"Covid is on the increase again but what is different this time is that we are seeing more medical and surgical activity at the same time. We also have a high number of staff having to self-isolate"
"If you are accessing services please be advised that your wait may be longer than expected. We are doing everything we can to minimise that, but the pressure on the system is significant"