Mayor of London Sadiq Khan is backing the charity-run Missing People Matching Tool, which will help those working with rough sleepers spot those who have been reported missing.
The tool cross-references information from the mayor's "Chain" (Combined Homelessness and Information Network) database of people sleeping rough in the capital with charity Missing People's records of the thousands of people reported missing every year.
Last year Missing People, which provides a free and confidential 24/7 helpline, support services and ways to find missing people, helped more than 10,000 children, young people, vulnerable adults and families.
Using the tool, if a homeless person is found to have been reported missing, outreach workers would offer help including offering to let their friends and family know they are safe, facilitate a reunion, or simply acknowledge their safety and remove their name from the missing persons database.
The online tool meets data protection and confidentiality requirements by only using a limited amount of personal information - names, date of birth and a photo - which is used for the matching and is then deleted.
When someone is matched, it is up to them to decide how they want to proceed.
The project, which is being piloted in London but could later be rolled out nationwide, has received the funding from the mayor's Rough Sleeping Innovation Fund.
Khan said: "The increase in rough sleeping in recent years across the country is a national disgrace and tragically it is often the most vulnerable in society who find themselves homeless.
"It is crucial we do all we can to help people off the streets of London, and I am pleased to be supporting Missing People's work to help reunite homeless people with their friends and family who love them."
Missing People's director of policy and research, Susannah Drury said: "This is just the first stage of this project - we hope that in time, more support organisations will link into the tool to enhance its reach and impact even further."
Petra Salva is director of rough sleeper, offender and migrant services at St Mungo's, which manages the Chain database and a number of outreach teams in London, said: "People can end up on the streets for many reasons, and people tell us that isolation and loneliness is a major factor.
"With this tool, outreach workers will be able to let people know they are being missed and looked for, but it will be up to the person themselves how they want to take things from there. Staff would support them whatever their decision."