Predictions for Z --> mu tau and Related Reactions

We discuss predictions for the lepton-flavour changing decays Z --> e mu, mu tau, e tau which may be searched for at the Giga-Z option of the Tesla Linear Collider project with Z resonance production rates as high as 10^9. We try to be as model-independent as possible and consider both the Dirac and Majorana mass cases. The Standard Model, if being minimally extended by the inclusion of light neutrino masses with some mixings as observed in neutrino oscillation search experiments, predicts completely negligible rates. With a more general neutrino content quite interesting expectations may be derived.