St Marys duty officer Inspector Kevin Dodds believed teenagers would think twice if they knew of the consequences of their actions.

He was part of Operation Lorn, a large scale crackdown targeting graffiti and anti-social behaviour in the St Marys and surrounding areas last weekend

Around 100 uniformed and plain-clothed officers from Rail Vandalism Task Force, RailCorp security, StMarys and Penrith police, school-liaison officers and specialist Public Order and Riot Squad, Polair, Mounted Unit and Dog Squads were involved in the two day operation.

They made 31 arrests and searched 136 juveniles at graffiti hotspots in StClair, Erskine Park, Cambridge Park and at train stations between Emu Plains and StMarys.

Teenagers caught spray painting at a St Clair sports ground were shamed in front of parents, who said they supported the police.

Nine teenagers believed to be attached to The St Clair Crew were issued warnings.

``A number of arrests were made and some of those juveniles before the courts were refused bail,'' Inspector Dodds told the Star.

``It's not worth it if they think about the consequences and severe penalties.''

Initiatives has been implemented to target the issue, including a Penrith Council program education program aimed to tackle graffiti before it happens by education about the consequences of writing or spraying graffiti and its impact on the community.

About 90per cent of primary and secondary schools in the Penrith LGA have signed up for the program, the first of its kind in NSW.

More activities are being also organised at Penrith and Mount Druitt PCYC clubs to keep young people out of trouble.

More operations targeting graffiti and anti-social behaviour will be held in the coming months.

``Police won't take a backward step and ensure these people are caught and put before courts, which are jailing graffiti offenders,'' Inspector Dodds said.