A convicted paedophile has left Christchurch after a public backlash sparked by a social media page aimed at identifying sex offenders.

The man's father, who declined to be named, said abusive phone calls and text messages had "resurfaced" since his son's photograph and details of his offending were posted online.

People had "sniggered and laughed" at his family in public, he said.

The social media page, set up a fortnight ago, profiled more than 60 convicted sex offenders from Christchurch and attracted more than 450 supporters.

It was shut down but a second page emerged to "promote the awareness of Pedophiles and rapists living in our community (sic)", using information from the Sensible Sentencing Trust website.

The page creator, who would only give her name as Emma to protect others living with her, has served separate stints in prison after an assault and knifepoint robbery.

The convicted paedophile's father said his son had tried to move on with his life since being released from prison in September 2013 after a conviction for unlawful sexual connection and indecent assault of a minor.

His son had a job, a partner and a young daughter but left town to escape the vitriol.

"She [Emma] says she deserves a second chance in life and she's turned her life around. How does she know these paedophiles haven't turned their lives around?" the father said.

A second convicted sex offender named on the page told The Press Emma failed to paint the full picture because some sex offenders had name suppression.

"That's the danger I find with those sort of pages . . . [not] everybody's on it."

According to a sex offender index, the man was jailed for indecent assaults on four boys in the 1990s.

Another convicted sex offender said he expected the social media page to be the centre of discussion at a relapse prevention meeting next month.

Emma said she realised not all convicted sex offenders in Christchurch were on the page but "I would be doing a lot more if I could".

She wanted to conceal her identity, fearing she may put children living with her at risk.

She said she understood claims of hypocrisy after stints in prison for assault in 2007 and holding a dairy shopkeeper at knifepoint in 2011. She was released from prison for the latest incident a year ago and had not reoffended, she said.

Emma said she was sexually assaulted in January 2007, and that largely led to her offending.

She said she regretted her actions and asked people to consider her social media page as "paying it forward".

She wanted members to refrain from posting "derogatory comments" or reacting with violence.

A Department of Corrections spokeswoman said information on the social page was publicly available. There were no complaints to Corrections about the page, she said.

The Sensible Sentencing Trust said Emma could share information from its website, as long as it was not altered.