It's estimated a quarter of young people in the country are having sex before they turn 16.
The first national survey of heterosexual sex in New Zealand for decades has revealed that by the age of 17, half of all New Zealanders have had sex.
It also revealed that having sex younger than the age of consent is more likely among Māori and Pasifika men.
More than 10,000 adults were surveyed between 2014 and 2015 on their sexual behaviours and data is being released for the first time.
Ministry of Health's deputy director of public health Niki Stefanogiannis said condom use was on the rise among young people and that was encouraging.
"The proportion of young people who use condoms the first time they have sex ... have almost doubled from the '70s," she said.
"Eighty percent of 16 to 24-year-olds are using a condom the first time they have sex which is really, really good and is something we want to continue."
But she said the results have highlighted some concerns.
"Māori are more likely to have sex at a younger age, less likely to use condoms the first time and these are areas that are really important to delve into and find out a bit more about so we can identify what kind of policies we can develop," Ms Stefanogiannis said.
More than half of adults who have multiple sexual partners also do not use a condom every time.
All data from the survey will be made public next year.