A measles outbreak which has infected more than 120 people in the upper North Island is continuing to spread.
There have now been 109 confirmed cases in Auckland, where the outbreak originated, and 19 confirmed and one suspected case in Waikato, one of which has required hospitalisation.
Cases have also been reported in Taupo and Northland.
Medical Officer of Health Dr Anita Bell said of the 20 Waikato cases, 19 had not been immunised and one had received only one of the recommended two doses of the measles, mumps and rubella (MMR) vaccine.
"This is a testament to the effectiveness of the MMR vaccine in protecting people who are fully immunised.
"Immunisation is the only protection from this potentially serious disease. Immunisation protects not only the individual, but also blocks the spread of this disease within our communities.''
Dr Bell said anyone displaying symptoms of measles, which include fever, cough, blocked nose, sore red eyes, should immediately phone their doctor or Healthline on 0800 611 116.
Ministry of Health immunisation manager David Wansbrough said vaccine distribution figures showed a "significant increase'' in demand for the vaccine this year.
Children needed two doses of the MMR vaccine to be fully immunised - one at age two and the second two years later.
The National Immunisation Register showed 90 percent of children received the first dose but only 75 percent had both.
There have also been two cases of rubella confirmed in the Auckland region.
- NZPA