The River Environment Classification (REC) provides a GIS-based tool to differentiate between biophysical attributes of river systems. This study tests the effectiveness of the REC as a tool to differentiate physical habitat and macroinvertebrate assemblages between four classes of stream in the Auckland region. Results indicate significant within-class variability in physical habitat and macroinvertebrate assemblages, with considerable overlap among the four classes. Biophysically meaningful stream classes cannot be identified from GIS-derived data applied in this research. Field analyses of physical habitat (i.e. geomorphic river condition) are required as a supplementary tool to interpret ecological relationships for differing stream types.