Bruce Barnes, of Smith Avenue, pleaded guilty in the Warrnambool Magistrates Court to committing an indecent act with a child aged under 16 years.

He was convicted and sentenced to six months in prison - suspended for two years.

Barnes was also fined $2000, has to pay $836.10 costs and will be on the sex offenders' register for eight years.

The court heard that during November last year Barnes had a party at his home which was attended by his children and some of their friends.

A witness saw Barnes in the kitchen with his arms around the 15-year-old victim and he kissed the girl on her lips.

It was not a really long kiss but it was "weird" and the witness was "grossed out".

Earlier that month, a witness saw Barnes in his bedroom with his arms around the 15-year-old victim, kissing her.

"It was a lover's kind of kiss," the witness said.

The witness was shocked and "thought it was pretty sick" because Barnes was 35 years old and the victim just 15.

Defence counsel Sally Dixon said Barnes had never previously been in trouble and he knew his behaviour was inappropriate.

She said Barnes had initially denied the charge because he was embarrassed, but now accepted full responsibility.

Ms Dixon said her client's conduct was at the lower end of the scale and there was no suggestion he went beyond kissing.

There was no victim impact statement and the court heard the victim had a different version of events to the witnesses.

Magistrate Jonathan Klestadt said Barnes' conduct was wrong and obviously inappropriate.

He said Barnes was a mature man and had kissed the girl in an erotic way that went far beyond what was acceptable.

Mr Klestadt said Barnes had been involved in an act of great foolishness rather than predatory, perverse or pedophilic behaviour.