The N-Dubz star has apparently been smoking backstage and allowing friends to hang out with her until the early hours.
Studio staff can't close the building until the parties have finished because she refuses to leave, The Sun claims.
"It's just not very professional. She's smoking in her dressing room in the breaks and it's full of her chavvy pals all drinking from her minibar," a source said.
"When they won't leave it means the security staff are stuck there waiting to lock up."
Producers apparently want the judges to set better examples for their acts after Rylan Clark and Lucy Spraggan were kicked out of London's Corinthia Hotel. It is feared all the contestants could be asked to leave over their increasingly wild behaviour.
