I believe most folk are worried, and the media has been referring to it as a "housing crisis". Notably the price increase has been limited to Auckland though (and Queenstown, but Queenstown is the NZ equivalent of Aspen, Colorado; which is to say it's a bit of a millionaire's club).
Unfortunately the currently in power government has done a lot to court this outcome, and so has mostly been avoiding doing anything about it. I think they did recently step in to make it harder for Chinese investors to purchase property in NZ though.
Average house prices in Christchurch just hit half a million, so it's not limited to Auckland and Q'Town, it's just that they were already crazy markets in the first place.
LVR restrictions were upped in October to 40% meaning you now need as an investor 40% deposit for a mortgage in Auckland from the NZ banks (previously was upped to 30%). Things might be slowing down - open homes in my area seem to have less traffic on weekends ....
Unfortunately the currently in power government has done a lot to court this outcome, and so has mostly been avoiding doing anything about it. I think they did recently step in to make it harder for Chinese investors to purchase property in NZ though.