Rio Tinto's announcement that it was doing a review that could lead to the closure of the Tiwai Pt aluminium smelter sparked alarm.

Well over a billion dollars was wiped off the market value of electricity generators in the hours following, as investors considered the prospect of a sharp drop in demand.

Invercargill MP Sarah Dowie warned that Rio Tinto's announcement, combined with other troubles hitting the region meant Southland "will be destroyed".

NZ sharemarket blindsided by Rio Tinto's review of Tiwai Point smelter
Owners of Tiwai Pt aluminium smelter seek talks with the Govt, raising possibility