Flavour changing top decays in supersymmetric extensions of the standard model

Flavour changing top decays $t \to c Z^0, t \to c g$ and $t \to c \gamma$ are predicted with invisible rates within the standard model and may represent a window on new physics. We consider these processes in supersymmetric extensions of the standard model and we show that observable rates can be obtained only if the SUSY breaking is non universal and flavour dependent.