The storm lifted roofs, toppled trees, shattered windows, downed powerlines and sent trampolines flying in the suburb of Papatoetoe at around 8:30am.
RNZ reports a worker was killed when the tornado struck a freight container hub in Wiri Station Road.
The deceased is a former Fijian who moved to New Zealand in 2014.
Two other workers who were taken to Middlemore Hospital - one is in a moderate condition and the other has minor injuries.
Several containers were toppled by the strong wind.