By Sally Whyte and Elizabeth McKenzie
Community fears have been heightened with reports a known sex offender has been seen loitering near children in Melbourne.
In a separate incident, police are investigating reports that a man approached a boy at a Daylesford school on Thursday afternoon. The boy notified a teacher, who passed the information to police.
Former head of Victoria Police's child protection squad Chris O'Connor, said the community is understandably alarmed at such cases.
Mr O'Connor said he is comforted that in 2014 the community is positively responsive to this kind of activity.
Mr O'Conner said there are thousands of people on the sex offender registry, and 24 hour police surveillance would be impossible.
'There are thousands of people on the registry we clearly and very quickly come to the realisation that we would never have enough police to be able to satisfy totally the community as to their level of protection against these people.'
Mr O'Connor says parents have a responsibility to protect children, but warns against the public taking the law into their own hands.
'Vigilantism is often the result of a couple of things, victimisation or ignorance or a total lack of understanding of the circumstance. It is irrational behaviour.'
Mr O'Connor said children should be educated about how to respond in the unlikely event they come into contact with sex offenders.
'Teach them basic crime prevention, be aware of who is around, remove yourself or call out to somebody. If somebody approaches you, you yell the living daylights out.'