Sarah Payne was murdered by a convicted sex offender
A scheme giving parents details about sex offenders who may come into contact with their children is being extended.
Home Secretary Jacqui Smith said pilot projects in Southampton, Warwickshire, north Cambridgeshire and Stockton had given children a "better deal".
The scheme will be rolled out to the whole of those police force areas.
A campaign to let parents have more information came after the murder of eight-year-old Sarah Payne by convicted sex offender Roy Whiting.
More than 150 parents have made inquiries under the trial scheme which started last September.
Of these, 10 were given relevant information.
There were fears such a system could lead to vigilante attacks against offenders but there have been no cases so far.
Ms Smith told the News of the World: "Drawing in families and allowing them to take responsibility and share their concerns with the police is a positive way forward.
"In tackling crime you need people to stand alongside police. And in the police areas where the schemes have been operating I would say we are giving children a better deal."
The so-called Megan's Law in the US, which allows the publication of names, addresses and pictures of paedophiles in some states, prompted calls for an equivalent "Sarah's Law" in the UK.
The extension of the UK trial could lead to a national system of alerts.
Sarah Payne's mother Sara, who is the government's 'Victims' Csar', said: "I would say we are giving families a better deal by including them in child protection."