Two out of three New Zealanders did not use any form of protection the first time they had sex, a survey has found.
That is a disappointing figure given the high risk of sexually transmitted infections and even Aids, sexual health experts say.
The study, which is released today, was commissioned by the worldwide condom manufacturer Durex in a bid to raise the profile of World Aids Day today.
Last year 149 people were diagnosed with HIV in New Zealand.
The study surveyed up to 29,000 people aged 18 and over from 36 countries, including 510 from New Zealand.
Figures showed that two-thirds of the Kiwi men and women surveyed said they did not use any form of protection when they lost their virginity.
The main reason given by 42 per cent was that they trusted that their sexual partner was free of sexually transmitted infections; however a quarter of them admitted that they were unsure whether their partner was free of infection.
Family Life Education Pasifika manager William Pua, who has been a sexual health educator for 11 years, said the figure was disappointing.
"That's an issue that really needs to be addressed. We know that the STI rates have not been good.
"In general, people are quite trusting. They think their partner is monogamous and therefore clear of any STI. But I think that's a naivete that we really need to address."
Mr Pua, whose organisation has a particular focus on Pacific people, said its education programmes included going out to schools and putting out the safe sex message through music and theatre.
He said people also needed to communicate better about sexual health and the need to be aware of the dangers.
"The issue of protection is important - it's not just about contraceptives. It's also about how we teach and how we talk ... the need for clear communication and to talk openly about these things."
Clinical director Jane Morgan, who works at the Hamilton Sexual Clinic, said most people tended to trust a sexual partner and so would not use protection.
One message health practitioners struggled to get through to people was the idea that they needed to be tested regularly if they were sexually active.
"A common thing we hear from patients is that they believe that they would know if something was wrong ... [but] a lot of the common infections like chlamydia do not cause symptoms."
Dr Morgan said there was no room for complacency, given New Zealand's appalling sexually transmitted infection rates.
"The only 100 per cent sure way to prevent infections is by not having sex. If you choose to have sex, using condoms and having a monogamous uninfected partner helps lower your risk.
"The only way you can tell if somebody's infected ... is to get tested."