Documentary makers claim to have made a “major breakthrough” in the Madeleine McCann case.
The findings are being shown on Channel 7’s Sunday Night in Australia, with viewers promised a “landmark television event”.
But those behind the show have kept their findings secret, only releasing a 40-second teaser trailer.
A spokesman for parents Kate and Gerry McCann told the Daily Star that any new information should be passed to the authorities.
He said: “If the Australian TV show contains any credible, fresh lines of inquiry they should, of course, have been given immediately to the police.”
The programme features Goncalo Amaral, the Portuguese policeman who initially led the investigation into the tot’s disappearance.
Forensic scientist Dave Barclay is also features, branding it “the most baffling” case he has seen
The documentary comes as the family prepare to mark the 10th anniversary of their child’s disappearance.
Maddie vanished from the Praia de Luz holiday resort when she was just three years old.
Last month the Home Office gave £85,000 to fund the hunt for the youngster, dubbed Operation Grange, so that the probe could be extended until September.