The closure of Dunedin and Wakari hospitals is continuing on Tuesday as Otago District Health Board tries to contain an outbreak of norovirus.
About 80 patients and staff have the highly contagious gastric complaint, and only the department's emergency, maternity and psychiatric departments remain open.
More than 800 outpatient appointments and elective surgery appointments were cancelled on Monday and a similar number are expected to be affected on Tuesday.
Dunedin health officials believe the norovirus is likely to be affecting the wider community, and they are warning anyone with symptoms to stay home.
Medical Officer of Health John Holmes says norovirus is a non-notifiable disease that is tested for only when two or more cases linked to a common source occur.
Dr Holmes says discussions with local GPs suggest the illness, which causes vomiting and diarrhoea, has hit the wider community. He says it has appeared in rest homes and private hospitals as well.
He says anyone with norovirus symptoms should stay at home for several days to prevent the bug from spreading.