"Staggeringly high" rates of chlamydia have been reported among New Zealand teenage girls.
A report by Environmental Science and Research (ESR) was the first time data was collated from every laboratory in the country on people tested, as well as the number of new sexually transmitted infection (STI) cases found.
It found 5064 cases of chlamydia per 100,000 population in teenage girls aged 15 and over.
This was a "staggeringly high" rate, the report authors said.
Because only six per cent of teenage boys were tested for STIs, compared to 35 per cent of teenage girls, the real number of men with chlamydia was likely higher.
Sexually transmitted infections other than HIV/AIDS are not legally required to be reported to government authorities. Reports like ESR's rely on voluntarily contributed data.
It showed national rates of chlamydia have fallen overall between 2009 and 2013, although the number of cases found at sexual health clinics had increased by 10 per cent.
New Zealand's rate of chlamydia was markedly higher than Australia's (633 compared to 355 per 100,000 of population).
Cases of genital warts seen in sexual health clinics were down 44 per cent. The reduction was most notable in teenage girls.
This was likely due to the introduction of the Gardisil vaccine in 2008, a Government-funded option taken up by more than half those eligible for it.
Gardisil protects against human papillomavirus that causes genital warts and cervical cancer.
Should fluoride in water be the responsibility of central government?