The Healthy Ministry (MOH) is in the process of identifying those who were in close contact with an infant who had measles on a Singapore Airlines (SIA) flight.
MOH said it would get in touch with them to check on their health and advise them to seek treatment if unwell.
The infant's family were travelling on board SQ281 to Auckland on January 12 via Singapore.
MOH said it is also working closely with New Zealand authorities and SIA.
According to reports, the infant's family had been in the Philippines for six weeks and had flown home to Auckland via Singapore on a 10-hour flight.
The infant was admitted to a hospital in Auckland on January 13 and was tested positive for measles.
This prompted the New Zealand's Regional Public Health Service to issue an alert.
According to reports, the infant was discharged on Wednesday.
According to a SIA spokesperson, Auckland's health authorities were the ones who informed the airline.
SIA said it is helping both Singapore and New Zealand Health authorities with contact information of passengers who were seated close to the infant.
More than 270 passengers were on board the flight.
Experts Channel NewsAsia spoke with said measles, which is a notifiable disease in Singapore, is highly infectious.
Signs and symptoms include a bad rash, fever, conjunctivitis and a cough.
However, the risk of an outbreak in Singapore is rare as most Singaporeans have had at least two doses of the measles, mumps and rubella (MMR) vaccine.
In Singapore, the first dose of the vaccine is given at 12 months of age, and until 2011, the second dose was given in Primary One.
Associate Professor Lim Poh Lian, Head of Department for Infectious Disease at Tan Tock Seng Hospital, explained: "In 2010, there were 54 cases out of five million people but in 2011, it had gone up to 143, which is almost a tripling of the measles cases.
"At that point, the Ministry of Health changed the policy to bring the measles vaccinations down, to the second dose being given at 18 months of age, to protect all Singaporeans."
Prof Lim added: "Infants under 12 months of age would be potentially vulnerable if they were exposed to measles. The other group of people that might have some risk of measles are those who may have missed measles vaccination in childhood, such as those born overseas in developing countries, perhaps from poorer families.
“Another group of people would be those who are middle-aged: in their 30s or 40s, when the recommendation for measles vaccine was one dose instead of two."
If there is an outbreak, health authorities would also get involved to have those exposed to get checked or vaccinated.
MOH said there were 46 confirmed measles cases last year and 38 cases in 2012.
A majority of them were children aged below 12 months.
MOH said the vaccination coverage of measles, mumps and rubella (MMR) has been consistently above 95 per cent.
It added the risk of community outbreak of measles is low because most people would already be immune either through vaccination or natural exposure.