The application is a joint initiative between the website and CEOP, the Child Exploitation and Online Protection Centre, which tackles the sexual abuse of youngsters, including "grooming" through the Internet.
Users will be able to bookmark the ClickCEOP service or add it as an application to find information about online safety.
CEOP Centre chief executive Jim Gamble said they knew from speaking to offenders that a visible deterrent could protect young people on the web.
Calls for the inclusion of a "panic button" for youngsters grew in Britain earlier this year after the conviction of a serial rapist who used the site to pose as a young boy to lure and murder a teenage girl.
Joanna Shields, Facebook's vice president for Europe, the Middle East and Africa, added: "There is no single silver bullet to making the Internet safer but... we have developed a new way of helping young people stay safe online.
"It is only through the constant and concerted effort of the industry, police, parents and young people themselves that we can all keep safe online."
Britain's crime prevention minister James Brokenshire said: "It's a sad fact that we are now seeing more cases where sex offenders are using social networking sites to conceal their identities in order to contact children.
"While this solution provides real help it is also vital that government continue to work with industry, police, and parents to educate children about the dangers they may face online."