It's been on the cards for quite a while. Chairman Wheeler has been pretty clear about it. The RBNZ publish their expected track for short term interest rates and right now they expect to be ~5.25% by around March 2017. I'm not quite sure whether will get there (we'll be at $1/US$1 by then!) but rates are assuredly going up, and likely will continue aggressively. The US and UK will start raising rates as well soon (call it within a about a year) which will tamper the rise of the Kiwi but for now NZ stands ahead of the pack for rate rises in developed countries. The RBNZ are well aware that they can't manage the currency. Some NZ$100bn is traded every day, the 10th or so most traded currency. Not bad for a country of 4.4mm. So it's not that they don't care how high the currency goes because of the rate rises, they know they can't manipulate it like e.g.. the US with money printing or the Chinese. In the end it will be things like milk and log prices coming down (we're going gangbusters with exports to China) that will bring down the value of the Kiwi.