The singer was a judge on the first two series of the show but quit this year to focus on her music.
However Jessie's still a fan of the show and has been tuning in, although she wasn't too impressed with what she saw at the weekend.
Jessie hit out at the panel for their lack of "vocal criticism" of the acts as the battle rounds got underway.
The former coach was particularly critical of the new judges after Team Tom's budding performers Mairead Conlon and Celestine sung-off against one another with Jessie's hit song It's My Party.
“Where is the constructive vocal criticism?!" Jessie complained on Twitter. "It was TOO MUCH! Vocally messy and too many runs and licks!"
Jessie continued to slate the show for not giving any negative feedback at all.
She told her followers: "Singers don’t and won’t improve if you continually say ‘amazing’ when it’s not… Can’t get better in a ‘Yes bubble’.”
The 25-year-old later added: "Every singer has to take criticism! Myself as an artist included! And I know if I performed 'It's my party' like Team Tom did on the battles that my team wouldn't say it was great. And I wouldn't want them to.
"The TRUTH is the only thing we can build from! And make it better! So be reaaaaaaal!"
Almost 7 million viewers watched the battle rounds on BBC One at the weekend but it was the lowest ratings of this series.
The Beeb show did however narrowly beat Ant and Dec's Saturday Night Takeaway by a margin of just 0.03 million viewers.