More Australian teenagers are viewing porn and doing so at a younger age than ever before, according to new research.

Key points: Study found almost all young Australian men frequently watched porn

Study found almost all young Australian men frequently watched porn Porn watching starting at younger age, 13 for boys, 16 for girls

Porn watching starting at younger age, 13 for boys, 16 for girls Call for porn to be included in high school sex education classes

Burnet Institute researcher Dr Megan Lim, who did the study, said she was surprised at how commonly pornography was viewed by Australians aged 15-29.

"All the young men in our study said they'd seen pornography, and so did the majority of women," Dr Lim said.

"They also reported seeing pornography at quite high frequency."

The study of more than 940 young people found the typical age for boys to view porn for the first time was 13, and 16 for girls.

"Around 80 per cent of young men said they watched weekly, and among the women who watched pornography, nearly two-thirds viewed at least monthly," Dr Lim said.

Researchers identified a link between pornography use, mental health problems and becoming sexually active at a younger age.

"We're not out to prove that watching porn is a bad thing. But definitely watching pornography more frequently is associated with some negative outcomes such as poor mental health, though we can't say from this study if one is causing the other," Dr Lim said.

They also found young people identifying as lesbian, gay, bisexual, transgender, intersex, and queer watched pornography more frequently and from a younger age.

Dr Lim said the findings of the study had important implications for developing relevant sexuality education.

"While we're not clear on what kind of influence it might be having on [young people's] sexual development, with such high rates of use pornography needs to be considered in teaching people about sex in a changing world," Dr Lim said.

She said appropriate sex education needed to be implemented in high school, if not earlier.

"I'm not suggesting schools provide details about how to have anal sex, but they need to acknowledge it does exist in the real world as well as in porn and to discuss the differences in how it's portrayed in pornography as opposed to how it's practiced in the real world," she said.

"Pornography is designed for entertainment and it's a performance. It doesn't reflect what people necessarily do in the real world."

What they found:

Frequent users of pornography are more likely to be male and well-educated

Frequent users of pornography are more likely to be male and well-educated The average age of first exposure to pornography is declining

The average age of first exposure to pornography is declining The median age of first viewing is 13 years for boys and 16 years for girls

The median age of first viewing is 13 years for boys and 16 years for girls Interventions such as age verification and internet filtering software are not likely to be effective in preventing a motivated young person's access to pornography

Interventions such as age verification and internet filtering software are not likely to be effective in preventing a motivated young person's access to pornography There's a correlation between the use of pornography and poor mental health.

Researchers also found young people who did not identify as heterosexual often felt excluded from sexual education at school, which is often focused on heterosexual behaviour.

"Our hypothesis is that these teenagers are being missed in traditional sex education and even in the media," Dr Lim said.

"There's very little information out there for diverse groups.

"So young people may be seeking further information about things they're curious about, and one of the only ways they're able to access that is through pornography."

The study, based on an online survey of 941 participants recruited via social media in 2015, is published in the Australian and New Zealand Journal of Public Health.