A concertgoer who urinated on a woman at a Spiderbait gig has had his bid to avoid a criminal record knocked back and instead been convicted and docked $800.

Joel Ryan Morrison previously denied urinating on Belle Nolan at a Melbourne gig on February 26 last year, but on Tuesday admitted to his crime in the hope he would be put on Melbourne Magistrates Court's diversion program, which spares first-time offenders a criminal record.

But magistrate Franz Holzer said a diversion was inappropriate and a sterner penalty was more apt.

"I'm going to refuse the application ... the matters are frankly disgusting," Mr Holzer said.