There are calls for mandatory GPS monitoring of serious sex offenders amid revelations of a spike in the number of sex pests loitering near schools, parks and childcare centres.

Victoria Police reported 35 incidents where serious sex offenders were found loitering near what are referred to as ‘child heavy’ areas last year.

The Herald Sun has revealed that’s the highest number since 2012.

There are 41 serious sex offenders out in the community having done their time behind bars, but Corrections Victoria won’t say how many have court ordered tracking devices.

Police are urging parents to remain vigilant and report any suspicious behaviour.

But Victoria’s victims of crime Greg Davies says we should go further and make GPS monitoring of all serious sex offenders mandatory.