Spanish agency Metodo 3 has cost the dwindling Find Madeleine fund £50,000 a month since September, but has so far failed to find any concrete evidence about what happened to the girl.
Its director Francisco Marco also angered the McCanns with a series of public boasts that he knew where Madeleine was and would find her within five months.
The agency's six-month contract is up for renewal in March and a source said: "We will carry on the search for Madeleine, but not necessarily with Metodo 3. We are stuck with them to the end of the contracted period. The question of whether it is renewed or not has still to be decided. They have faced not having their contract renewed every since Francisco shot his mouth off... It was made clear what they were doing was foolish and unhelpful."