St John ambulance staff have been quarantined as Auckland's measles outbreak continues to spread.
Since June, there have been 182 confirmed cases of measles in the city, with 11 in past week.
St John medical director Dr Tony Smith said one Auckland staff member has been confirmed to have become infected with measles.
"The staff member has been off work but not sick enough to be admitted to hospital," he said.
"The diagnosis was confirmed at the end of last week and we do not know how they became infected."
"Also, a small number of staff have been quarantined because they were in close contact with people who have had measles. We are organising testing for them to clarify their immunity status."
Dr Smith said St John is working on an immunisation campaign for staff without immunity to measles.
He said ambulances are cleaned after every patient who may be carrying an infectious disease.
If you think you have measles visit your doctor or phone healthline, 0800 611-116.