Two people are dead and more than a dozen are sick after a suspected norovirus outbreak.
The outbreak has shut part of an Auckland rest-home where more than 180 elderly people live.
Auckland Regional Public Health Service clinical director Dr Julia Peters said last night everything was being done to contain the spread of the highly contagious illness.
Outbreaks of norovirus were not unusual, but deaths were uncommon, Dr Peters said.
The Institute of Environmental Science and Research said 10 people died from the virus last year.
Those hit by the latest outbreak all live at St Andrews Village - a 14ha retirement centre in Glendowie, which offers services from specialist hospital care to rental cottages.
The hospital section of the centre has been closed to visitors after an outbreak of gastroenteritis, which the Public Health Service said was probably caused by norovirus.
The two people who died were in hospital with other illnesses so it could not be said for sure that norovirus had killed them, Dr Peters said.
"But if elderly people are debilitated and already hospitalised, they are hit harder than a healthy person who can shake it off."
Another 13 people were struck down with the symptoms of vomiting and/or diarrhoea, but Dr Peters said about half were showing signs of recovery.
St Andrews Village management was not available for comment last night.
Although there have been larger outbreaks of norovirus, this is understood to be one of the most deadly. Dr Peters said steps taken to manage the outbreak included isolating affected patients, making sure hand hygiene was thorough, and extra cleaning of surfaces likely to be contaminated.
"It is all being done by the book - they are doing everything they can."
Dr Peters said norovirus was not uncommon in institutions and was very contagious.
Samples had been sent for laboratory testing, and results were due back early next week.
Dr Peters said it was not always possible to determine the cause of an outbreak.
"It could arise from a range of possible internal or external contacts with patients. Unfortunately this is not unusual and there is a higher tendency towards outbreaks of this type in elderly institutions."
