John Marrapodi said the holiday period was an opportunistic time for vandals to target schools.
‘Unfortunately, there were more than 3000 acts of vandalism on public schools this year, but we hope community vigilance can prevent further incidents during the holidays,’ he said.
School Watch security staff will patrol schools during the holidays, to help deter vandals.
Mr Marrapodi said suspicious behaviour to look out for included unusual vehicles parked at the groups, noises such as glass breaking and loud banging and groups of people gathering around the site.
He said people should call School Watch on 1800 177 777 or the police on 13 14 44 if they see anything suspicious.