A person suffering from measles who ignored instructions to go into quarantine has potentially put hundreds of people at risk of catching the illness.
An alert issued today by the Auckland Regional Public Health Service said the infected person contracted measles on an international flight in late January.
Instead of isolating themselves the person roamed the SkyCity Casino and the exclusive Sugar Tree apartment complex on Union St.
The service says people in the public areas of levels 2 and 3 at the casino between 9.45pm and 12am on February 9, and the lifts and common areas in the apartments from February 9 to 13 have likely been exposed to the disease.
If they are not immune, they could get measles.
Symptoms would likely be felt from today and those who are not immune to the illness or are unsure about their status will need to go into quarantine for 10 days until February 27.
A SkyCity spokeswoman wouldn't answer questions about its response and if any staff were affected, instead referring NZME to the public health service.
Sugar Tree managing director Darren Brown said the apartments were contacted by health authorities yesterday.
"They proposed a letter that's gone out to all the residents at Sugar Tree explaining the situation and advising them of the course of action and what symptoms to look out for," Mr Brown said.
"We've distributed that letter today to people potentially effected, beyond just the residents of the building... We're doing everything we can."
There are 148 apartments in the affected stage one development building.
Auckland's medical officer of health Richard Hoskins said the law allowed people to be ordered into quarantine if necessary, if they were likely to spread an infectious disease.
Usually, a heavy-handed approach wasn't required.
The person who ignored the advice in this instance flew to New Zealand on January 30 on China Southern Airlines flights CZ305 and was sitting two rows behind an infected passenger.
Dr Hoskins had yet to consider the possibility of any action against the person.
"By ignoring our instructions this person has put the health of the public at risk. There are many people who could be potentially exposed to measles and they will need to take immediate action if they suspect they are not immune to this disease," he said.
"This is really disappointing. We don't want people to be spreading this to other people."
Dr Hoskins said people in quarantine should stay at home, not go to work or school and avoid having visitors. They also shouldn't visit doctors' waiting rooms without giving notice.
The illness is infectious before the tell-tale rash appears and can be spread by walking past or standing or sitting next to an infected person.
"My plea is that people follow medical instructions when they have been exposed to measles," Dr Hoskins said.
"For everyone else it's a timely reminder to check their immunisations are up-to-date. Measles cannot be treated once you get it so the only way to protect yourself is to be fully vaccinated.
"Measles is rare in New Zealand thanks to immunisation. We had two big outbreaks in 2011 and 2014 from people who were infected from overseas. People tend to underestimate measles - the reality is it can be a nasty disease."
First, a fever develops and one or more of a runny nose, cough and sore red eyes.
After a few days a red, blotchy rash starts on the face and spreads to the rest of the body.
People who suspect they have measles are asked to contact Healthline first on 0800 611 116 for advice.