Will I be allowed into Thailand with less than six months on my New Zealand passport?
timatic has (re Thailand):
Passports issued to nationals of New Zealand must be valid
for the period of intended stay.
- for holders of normal passports;
- Emergency and temporary passports issued to nationals of New Zealand must be valid for at least 6 months from date of arrival.
So I think your answer is "Yes", unless your passport is a temporary or emergency one or you are planning on a visit that is longer than the period between your proposed time of entry and your passport's expiry, and subject of course to the usual caveat that almost anyone might be refused entry for almost any reason.
The above assumes you do not need a visa. If you do need a visa then you do need at least six months remaining validity for your passport.
To enter Thailand, a passport valid for six months is required by all nationals referred to in the chart above.