By means of a global coupled sea-ice--ocean model we propose an oscillating mechanism in the Antarctic region with the same frequency as that associated with the Antarctic Circumpolar Wave (ACW) [White and Peterson, 1996>. Since our model is forced from the atmosphere with climatological monthly data with an annual repeat cycle, our oscillation suggests an internal mode of the sea-ice--ocean system rather than one which is dictated by global links through the atmosphere. This mode is robust for a wide range of parameterisation and forcing of Southern Ocean sea-ice, except for the case where higher rates of new-ice production and thus Antarctic Bottom-Water (AABW) formation are enforced. The present results imply that the sea-ice--ocean system itself may produce regional oscillations at a 4-year period in climatic conditions of relatively weak rates of AABW formation, which may contribute to regionally sustaining the ACW pattern. ¿ 1998 American Geophysical Union