According to this article this investigation was prompted because
... the PSTN network and so-called plain old telephone service (POTS) will be discontinued came in a document from the country's Ministry of Economic Development released last Thursday. Ostensibly, the document does no more than request comments about what the effect of the NGN plans will be on Telecom New Zealand's (TNZ) so-called "Kiwi Share Obligations" (KSO) - the requirement that the carrier provide basic phone service to all residents of the country, more formally called the Telecommunications Service Obligations (TSO). The KSO, the Ministry notes, was of "crucial importance" when TNZ was privatized in 1990.
The issue now is how TNZ will fulfil the KSO once its planned NGN is in place, and in order to discuss that - public comments are being solicited until Sept. 28 - it was obviously necessary to outline the issues. The biggest issue is turning out to be that, once TNZ converts over to an all-NGN, line-powered telephones won't work any more using power from the phone line because NGNs don't dish up the voltage that's standard on POTS.
Are we facing the same debate in the US as Verizon and AT&T's efforts to replace the copper local loop with fiber? Will New Zealand once again be leaders in telecom policy?