Barry Watters (35) has been living in the Salvation Army Granby Centre, on Granby Row, Dublin 1, and local families are terrified for their safety.
Watters was jailed last year after he admitted having child porn at his home. When he was convicted he was already serving a two-and-a-half year suspended sentence after being caught with graphic scenes of children being brutalised.
His sentence was suspended on a number of conditions, including that he complete a programme with the Granada Institute, that he not use computers or take any images of children on any mobile phone. He was also told he should not have unsupervised access to children.
Yesterday, parents and children walked in silent protest around Parnell Square.
Gerry Carney, a community spokesperson said: "We need legislation on this and in the interim we're looking for a protocol so that sex offenders are not to be put in high-density family areas."
The Department of Justice said: "A model of joint working between the gardai and the Probation Service is currently being piloted. It is being developed to ensure a comprehensive joint system of effective risk management is consistently in place."