Some may be state owned but they have delivered large dividends to the owners because they are run like private for-profit companies. Labour did nothing about the situation because it was like a hidden tax and we know how much they like tax. Fragmentation and competition leads to duplication of efforts and with it higher costs. Even the dividends paid out by the Auckland Energy Consumer Trust over the years would've been enough to give most recipients solar water heating. Energy saving technology like solar water heating isn't enthusiastically encouraged by interests that depend on profit from people paying for electricity. To make profits electricity needs to be scarce, they have absolutely no interest in securing lower electricity prices.

http://www.youtube.com/watch?v=fs2s67W2dOg

But electricity prices were always going to rise because we had cheap hydro electricity. The population has become too large to be supported by it without new dams, and the large increases in population brought by immigration demands continual invested in new infrastructure.