Medical professionals at the forefront of the measles outbreak have said there will be fatalities if the disease continues to spread.

Nine new cases have been recorded in Auckland since yesterday and seven more added to the national total.

As of 2pm today, there have been 821 cases of measles in Auckland, and 991 confirmed cases notified across New Zealand.

Eight adults and seven children are currently in hospital with the disease. One adult and one child are in critical conditions.

Starship clinical director Dr Michael Shepherd said some of the specific challenges they were facing were keeping other children safe, including immuno-compromised or at-risk children.

"I think that is something we can all get involved in as a community. I would really like to encourage people to think of others in this as well – and that is another reason for getting vaccinated.

"Because we are working really hard to stop people dying from measles."

As of 2pm Wednesday, there have been 821 cases of measles in Auckland, and 991 confirmed cases notified across New Zealand. 

Shepherd said it was difficult to see children having to stay home from school, and wear masks etc due to measles in the community.

He said the risk for immuno-compromised people was much higher.

"Measles is dangerous to everyone, and I think that we are going to continue to see serious illness and potentially death during this outbreak."

Shepherd said they'd treated a number of children who had been critically unwell, and they continue to have one case involving a person who is in a critical condition.

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"We are obviously trying our hardest to make sure they do well," he said.

He said the outbreak had added to the winter pressure doctors face anyway.

"It is another thing that adds pressure to the health system and of course it is very tough to see children, adults, others getting infection and illness that we can prevent. That is of course worrying.

"The message is we can all do something to help this; know your immunisation status, know whether you have been vaccinated, and if you are not sure then go and get it sorted out."

Meanwhile, Auckland Regional Public Health Service medical officer of health Dr William Rainger confirmed a student who attended the St Peter's College ball on Saturday did have measles.

It was earlier reported that the affected student was from another school and attended the ball as the partner of a college student before their symptoms began to appear.

Rainger said the service had been working with St Peter's College and the school the student with measles attends to ensure parents and students have clear advice on the level of risk from exposure.

Letters from ARPHS are being sent via schools to parents, informing them that their children may have been exposed.

Anyone who attended the St Peter's College school ball is recommended to go into quarantine from Saturday September 7 until the end of Saturday September 14, if they are not vaccinated or are not sure if they are vaccinated.