The owner of a Sydney cafe targeted by a graffiti offender says the three-month jail sentence handed to the teenager is too harsh.

Magistrate Ian McRae handed the sentence to first-time offender Cheyane Back yesterday for vandalising the wall of the Hyde Park cafe with a black marker last month.

The 18-year-old had pleaded guilty to damaging or destroying property.

She has been granted unconditional bail and has already lodged an appeal against the sentence, to be heard next month.

New South Wales Premier Nathan Rees has welcomed the three-month jail term because he says everywhere he goes, graffiti is an issue.

"This sends a message that it's not something that the community regards as a frivolous offence.

"It is something that affects not only the aesthetic but people's sense of safety around the place if they see graffiti around and they think there is other anti-social behaviour going with it.

"I think a three-month jail term is absolutely appropriate."

But cafe owner Song Wang believes community service is a more suitable punishment than jail.

"Give them more education, provide more education, and let them do some community service," she said.

University of New South Wales criminologist Professor Chris Cunneen agrees that the jail sentence does not match the scale of the crime.

"In the adult courts, a normal sort of penalty in relation to that offence would be a fine of some sort and some form of restitution for the property owner," he said.

"But I think there are other ways of approaching it. I'm not suggesting that a fine is the best way to do it.

"We've got some great examples from the Children's Court in terms of youth justice conferencing, which has been used in relation to graffiti, where you bring the offender together with the victim of the crime.

"You reach some sort of resolution and the offender is held responsible for the offence that's been committed and I think that's a much more preferable way of dealing with this."

Anti-vandalism community group Graffiti Hurts has applauded the sentence, saying graffiti costs Australian taxpayers $500 million a year.