Sarah's Law has helped protect more than 200 children from harm in its first year, new figures show.
Sara Payne, who campaigned for the law to be brought in following the murder of her daughter Sarah, said sex offenders could no longer hide their criminal history and put children at risk, the Press Association reported.
"If just one child had been kept safe as a result of Sarah's Law, then all the work to see it introduced would have been worth it," she said.
"The fact that it is hundreds of children is wonderful and testament to the fact the scheme is needed.
"Worried mums and dads must now be told if their child is in potential danger and it sends out a message to convicted sex offenders that they cannot hide their criminal history and put children at risk."
At least 160 disclosures relating to child sex offences have been made in the last 12 months, along with at least 58 concerning other offences, figures provided by forces to the Association of Chief Police Officers (Acpo) showed.
Overall, police received more than 1,600 inquiries and more than 900 formal applications under the child sex offender disclosure scheme, commonly known as Sarah's Law, which was rolled out to all 43 forces in England and Wales a year ago today.
It is a watered-down version of laws in the US under which details of where convicted paedophiles live are actively publicised.
Ms Payne, whose eight-year-old daughter was found in a field near Pulborough, West Sussex, after she was killed by convicted paedophile Roy Whiting in July 2000, led a high-profile campaign calling for a British equivalent.
Under the Home Office scheme, parents can ask police about anyone with access to their children and officers will reveal details confidentially if they think it is in the child's interests.
Police may also warn parents if concerns are raised by grandparents or neighbours.
Home secretary Theresa May said: "We are doing everything we can to protect the public, and especially children, from predatory sex offenders by tightening the law and closing loopholes.
"But families themselves have a vital role to play.
"It is important that parents, guardians and carers are aware of the disclosure scheme and their right to request information if they have concerns."
Assistant Chief Constable Michelle Skeer, the lead on the management of sexual offenders for police chiefs, added that one of the scheme's strengths is that it empowers "parents, carers, guardians and the wider public to take steps to protect children from harm".
It has also seen concerns being raised by close and extended family members and neighbours, she added.
"Where it is deemed necessary to disclose information to safeguard a child, this is done to the person who is best-placed to care for the child," Ms Skeer said.
"The actions of these members of the public have undoubtedly led to children being protected and helped to ensure greater public confidence in the police and other responsible authorities in the monitoring of sex offenders.
"When information is disclosed there is an agreement reached with the carer that this information must remain confidential to ensure the wider safety of the public."
Jon Brown, the strategic lead for sexual abuse at the NSPCC, said: "While Sarah's Law is helping to protect some children, we know there are many more still at risk.
"Last year there were more than 23,000 sexual offences reported against children in England and Wales. Everyone must play their part if we are to bring this worrying figure down."