The number of measles cases in Canterbury has risen to 30.
Canterbury Medical Officer of Health Dr Ramon Pink said the number was continuing to rise with one other case under investigation.
The total number of measles cases across the country has increased from 47 on Thursday to 50 today after two new cases in Canterbury and one in Auckland.
The latest Auckland case was a first-year student at Auckland University who attended law and business lectures last week where they may have spread the disease.
Auckland medical officer of health Dr William Rainger said the university was emailing information to those who were in lectures and tutorials for COMLAW 101 on March 11 and for ECON 151 on March 12, and in the BUSINESS 101 lecture on March 14 to keep an eye out for symptoms.
It was believed the student contracted the disease overseas.
Pink said there remained a risk of measles spreading when large groups congregated together.
"Measles is incredibly infectious and continues to circulate in our community. The only way to prevent its spread is immunisation," he said.
"If you were born after 1969 and feel unwell with measles-like symptoms, or have never been vaccinated against measles, you should stay away from large gatherings as you will be at risk of catching measles.
"And if you think you may have been exposed to measles or have symptoms, please call your general practice first, 24/7. Please do not visit your general practice or use public transport as you may be infectious."
With Canterbury residents last week racing to get the vaccine, another 27,000 doses arrived in the region last week.
Pink said that meant there was now enough to vaccinate everyone aged between 1 and 28 who had never been immunised.
Over time the vaccine would be made available to other groups such as those who had only received one dose.
A single dose of the measles, mumps and rubella (MMR) vaccine was 95 per cent effective in preventing measles and two doses was 97 per cent effective.
How serious is measles?
Measles is a serious illness. One in 10 people with measles needs hospital treatment and the most serious cases can result in deafness or swelling of the brain.
Measles is one of the most infectious airborne diseases and a person is contagious before the rash appears. It is very easily transmitted from one person to another, possibly by being in a room where an infected person has been.
I'm about to travel to a country that has a measles outbreak. What should I do?
The Ministry of Health is advising anyone travelling overseas to be up to date with their MMR vaccinations. In addition, the ministry recommends that infants aged 6-15 months travelling to countries where there is a current measles outbreak be given MMR vaccine before they travel. This is an additional vaccination for those infants – they will still need their usual MMR vaccinations at 15 months and 4.
What are the symptoms of measles?
Measles symptoms include a high fever, runny nose, cough and sore red eyes, followed by a rash starting behind the ears and spreading to the body a few days later.
How can I protect myself and my family against measles?
The best way to prevent measles is to be immunised on time, with two free MMR vaccinations for all children at 15 months and 4. Two doses of MMR vaccine are at least 97 per cent effective in preventing measles.
2019 measles cases by district health board
Counties Manukau: 1
Bay of Plenty: 2