The appeal was launched by the UK Child Exploitation and Online Protection Centre. Detectives hope the video will "prick the conscience" of someone who may be close to the girl's abductor.
The short film includes new images of how Madeleine might have changed more than two years after she disappeared while on vacation with her family in Portugal's southern Algarve coast in May 2007.
Madeleine disappeared from the resort a few days before her fourth birthday.
"If you know who's involved and are keeping this secret, remember it's never too late to do the right thing," centre chief Jim Gamble said in the film.
Gerry McCann, her father, told the BBC the video is an attempt to contact specific people rather than just appeal to the public for information.
"We need it to be spread far and wide, and for those people to be exposed to this message as many times as possible," he said.
The video is available in English, Arabic, French, German, Italian, Portuguese and Spanish. Police hope people will spread the film by way of blogs, e-mail and social networking sites.
