A major study into the sexual health and well-being of Australians – Sex in Australia 2 – reveals that sex in relationships occurs 1.4 times a week, down from the 1.8 times a week reported by more than 20,000 Australians who spoke to researchers a decade ago.

UNSW Professor Juliet Richters says the study, which includes details of the age at which people first have a sexual experience, the number of partners they have, who they have sex with and how satisfied they are, provides information that's essential for the development of policy and the delivery of sexual and reproductive health programs across Australia.

While younger people report having sex more often, people aged in their 60s reported having sex about once a week.

Emotionally, 86 per cent of men and 84 per cent of women reported their regular relationships were satisfying, with 88 per cent of men and 76 per cent of women saying the sex in the relationship was very or extremely physically pleasurable.

The researchers interviewed 20,094 men and women aged 16-69 between October 2012 and November 2013. The findings are reported in the journal Sexual Health.

While less than 20 per cent of people used condoms or other protection at first intercourse in the 1950s, the number is now more than 90 per cent.

When asked about the number of sexual partners they had during their lives, on average men reported they had sex with 18 women, while women reported they sex with eight men.

The number of people in same-sex regular relationships was not enough for the researchers to make analyses, they said.

Read more in the SMH and watch an interview with Professor Richters.

Media contact: UNSW Professor Richters 0414 273 234