The Wairakei-Tauhara geothermal system has been of interest as a modelling test case for a number of years. In particular it has been the subject of modelling studies at the University of Auckland since the early 1980s. The model presented here is the latest in a succession of these models. During the last 5 years the model has been significantly updated. Grid refinement, manual calibration and automated calibration, using the iTOUGH2 code, have been used to improve the model, which now agrees well with most of the available field data. (C) 2004 CNR. Published by Elsevier Ltd. All rights reserved.