Well, we don't actually hear her speak it face-to-face, but she was using it to get into the Chamber and control the basilisk-- at least, we heard somebody talking to the basilisk, and Tom-through-Ginny was the only one who could have. (I suppose it can be argued whether it was Tom-possessing-Ginny or Ginny-under-Tom's-control, but either way it was her body using the power.)

I'm not a huge fan of fanon Ginny but with a little Tom in her she's great.