An Auckland man has been found guilty after having a sexual relationship with a 13-year-old girl

Luca Fairgray's been on trial at Auckland District Court facing three charges of sexual conduct with a young person, two representative.

It's not disputed the pair had sex or that she was 13, but the defence argued the complainant said she was 16, and Fairgray believed her.

The prosecution says Fairgray got into a relationship knowing her age.