Speaking on the BBC Radio 4's The Media Show today, she said of it was "a shame" and "unfortunate" that Guardian editor Alan Rusbridger had decided to quit the Editors' Code Committee after a Commission report rejected his paper's phone-hacking allegations against the News of the World.
The Guardian has accused the PCC of being "complacent" and having no powers to properly investigate its allegations.
Baroness Buscombe told The Media Show presenter Steve Hewlett that the PCC could find no new evidence to support the allegations against the News of the World and accepted Rusbridger's claim that the Commission had no real investigatory powers.
She said: "He's right. We don't have serious powers to investigate. We are not a police force. We must not tread on the toes of the criminal justice system. We are more of a moderator."
Baroness Buscombe added that the PCC must not be used by organisations as "a political football" or allow itself to be "bullied".
She said the PCC had intervened to help Simon Cowell get the paparazzi off his doorstep and contacted the family of pop star Stephen Gately to see if they needed help keeping the "press at bay" following his death.