Seasonal ozone profiles, representative of the autumn and winter-spring periods, are computed from 20 ascents, made using electro-chemical sensors in sondes, for Christchurch, New Zealand. The seasonal changes between the autumn and winter-spring seasons are discussed in terms of changes in successive layers at different levels of the atmosphere, and are qualitatively similar to the well authenticated changes in midlatitudes in the Northern Hemisphere. The seasonal profiles at Christchurch (43S) are compared with the corresponding vertical ozone distributions in the Northern Hemisphere, and the results interpreted as suggesting that the vertical mass exchange processes are more effective in the middle stratosphere in the Southern Hemisphere during the spring ozone build up, but the trans-tropopause exchange is greater in the Northern Hemisphere. A sequence of profiles between 14 and 23 June is used to estimate vertical velocities using an appropriate ozone continuity equation and the results compared for consistency with vertical motion inferred from the thermal profiles.