Abstract Audiomagnetotelluric soundings in the frequency range 100-1 Hz have been made at three locations within the crater region of White Island volcano, New Zealand. Exceptionally low apparent resistivities are prevalent. Despite the possibility of terrain effects and static shift, and the three-dimensional nature of the island, the measured values appear to be indicative of the true electrical structure. One-dimensional modelling of the E polarisation responses has been used to obtain approximations to the electrical structure beneath each site. The results suggest a variable depth to the acid hydrothermal system which is believed to underly the crater region, with low resistivities coming closest to the surface near the active fumaroles of Donald Mound.