Doctors hope a new monitoring system will give clearer figures on the impact of the Zika virus on New Zealand children.
From next month all babies under six months with microcephaly, or other brain abnormalities, and whose parent has been in a country with the active virus just prior to or after its conception are to be reported.
The New Zealand Paediatric Surveillance Unit, which will receive the reports, will monitor the cases and establish just how many, if any, were directly related to Zika.
Unit epidemiologist, Nigel Dickson, said the monitoring will give medical professionals a clearer idea of how best to respond to the virus.
"I'm hoping to confirm that we have not got any children with this as a result of Zika."
He said six in every 10,000 babies born in New Zealand had the condition - a figure which could rise during a Zika epidemic.
During the 2015 outbreak in Brazil more babies were born with the condition, which is characterised by a smaller head as a result of poor brain growth, Dickson said.
"It is now clear the increase was due to mothers being infected by the Zika virus in the early months of their pregnancy."
He said something similar was seen during an earlier outbreak in French Polynesia during 2013 and 2014, when Zika was linked to an increase in babies born with microcephaly there.
Auckland-based paediatric infectious disease specialist Dr Lesley Voss said an accurate gauge of the situation in New Zealand was needed.
"It is important that we understand the situation here to make sure the appropriate advice is given to people who are considering visiting the Pacific while pregnant."
The virus is predominantly spread by the Aedes mosquito, which is not found in New Zealand, but is found in many parts of the Pacific.
For more information on Zika go to the Ministry of Health website moh.govt.nz
• Spread mostly by the bite of an infected Aedes species mosquito
• Can be passed from a pregnant woman to her fetus
• There is no vaccine or medicine
• Is active in parts of the Pacific and South and Central Americas.