Halliwell sat alongside Gary Barlow, Tulisa Contostavlos and Louis Walsh at auditions in Liverpool and was tipped to become a permanent replacement for Kelly Rowland.
However, X Factor bosses are believed to still be searching for a replacement after Halliwell failed to make a good impression, and the singer is said to feel uncomfortable that the job could go to her former Spice Girls bandmate, expected to be a guest judge in Manchester.
"There's only the smallest chance [Geri will] get the job full-time," Dan Wootton quotes a source as saying in his Daily Mail column.
"Geri feels it is disloyal of Mel B. But Mel has always done what is best for Mel, and that's why her relationship with the rest of the band is so frosty."
Mel B is unlikely to join The X Factor UK full-time though, due to her role on the Australian version of the show.
Leona Lewis, Rita Ora and Nicole Scherzinger have also been guest judges for X Factor auditions so far, while US singer Anastasia is the latest name rumoured for a stint.