Young people aged between 10 and 14-years-old are contracting chlamydia and gonorrhoea.

More than 28,000 people, including 465 children aged between 10 and 14-years-old, were diagnosed with chlamydia in New Zealand in a single year, latest figures show.

Statistics from the Institute of Environmental Science and Research show there were also 3038 positive tests for gonorrhoea in 2014.

Of those, 74 were young people between the ages of 10 and 14.

Figures for 2015 were not available.

Queen Charlotte College principal Tom Parsons, of Picton, said young people were engaging in risky behaviours, like drinking and sexual activity, at an earlier age than in the past.

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Sex was "everywhere" in the media, while peer pressure was also a factor, Parsons said.

"Society does appear to be a lot more permissive than it ever was before."

Sex education in schools had a vital role to play, but there were limits, Parsons said.

"Schools can teach the mechanics but it is very difficult to teach the relationship side of things."

More than 250 young people in Marlborough and Nelson, including five aged between 10 and 14, were diagnosed with chlamydia in 2014.

Chlamydia was most commonly diagnosed among the region's 15 to 19-year-olds, the report showed.

The highest number of positive gonorrhoea tests in Marlborough and Nelson was found in the 20 to 24-year-old age group in 2014.

There were 16 positive tests for the infection in that age group.

Marlborough Girls' College guidance counsellor Julie Saul said she was not surprised the number of sexually transmitted infections was highest in the 20 to 24-year-old age group.

"It is an age where people are becoming sexually active, and often sexually active outside of long-term, monogamous relationships.

"It would make sense as people get older and enter committed relationships their risk of getting a sexually transmitted disease drops."

However, positive tests for sexually transmitted infections were not just limited to young people.

The Institute of Environmental Science and Research report showed there were five positive tests for gonorrhoea, and 37 positive tests for chlamydia, among the over 40s in Marlborough and Nelson.

Nelson Marlborough District Health Board public health, rural health and district nursing service manager Peter Burton said the Picton Medical Centre had a sexual health service with a focus on sexually transmitted infections.

The weekly clinic worked in collaboration with the Blenheim Family Planning Clinic.

Sexually transmitted infection services were available to all ages that presented at clinics, including non-residents, Burton said.

The proportion of people reporting sexually transmitted infections across the different age groups in Nelson and Marlborough was similar to national trends, he said.

The Institute of Environmental Science and Research sexually transmitted infections surveillance report is released annually, and provides information reported by New Zealand sexual health clinics.