NHS Highland has confirmed that a third ward has been closed to new admissions due to diarrhoea and vomiting at Raigmore Hospital.
Ward 7A is the latest ward at the Inverness hospital to have confirmed cases of norovirus following Wards 2C and 6C earlier this week.
NHS Highland has placed a suspension on visiting on each of these three wards and a restriction on visiting in all other wards across the hospital.
Consultant microbiologist Vanda Plecko said: "We can confirm that a number of patients have tested positive for norovirus in Ward 7A. We have placed a suspension on visiting in Wards 2C, 6C and 7A for the time being.
"The suspension on visiting across all other wards has been lifted. However, we are asking for support from the public to help prevent the spread into other wards in Raigmore Hospital.
"We ask that visiting is restricted to two visitors per patient and would once again request that children do not visit the hospital. We would ask that anyone coming into the hospital needs to be clear of symptoms for at least 48 hours. By doing this we will limit the spread as much as possible.
"For the three wards affected (Wards 2C, 6C and 7A) we would ask that all non-essential visitors stay away from the hospital.
"However, if you feel that visiting is essential, please contact the ward first by phone before coming to hospital. Please do not visit the ward unless by prior arrangement with the nurse in charge."
The temporary suspension of visiting will be reviewed at the end of this week.
Patients in hospital can also keep in touch with loved ones via phone as the Hospedia system by patient beds can dial free, for the first two minutes of each call, to 01, 02 and 03 numbers.