A Te Anau man has been confirmed as having the second case of measles in the southern region in recent weeks, and the third case in the South Island.
Health officials believe they have caught the disease in time to prevent an outbreak of measles.
The Te Anau man's illness, and those of women in Milford Sound and Marlborough, were probably linked as they all knew each other.
The Te Anau man had been in isolation when he would have been infectious and was unlikely to have infected anyone else, SDHB medical officer of health Dr Susan Jack said.
"We're confident that contact tracing was effective and optimistic this incident is contained.''
The three cases were the first measles cases in New Zealand since May.
The World Health Organisation last year declared New Zealand to have reached endemic measles elimination status, meaning at least 95% of people were fully vaccinated against the disease.
Measles is highly contagious and can be life threatening. About one in 10 people with it will need hospital treatment.
The two earlier cases were diagnosed on November 20 and November 29, and sparked an urgent canvass of all the patients' contacts in case they had contracted the disease.
None of the three was believed to have been vaccinated against measles.
