PolicyGuy:
If NZTA / MoT are even vaguely thinking about adding an extra character to plate numbers, they need to start public and trade consultation Real Soon Now.
Nah, as for all the reasons you listed I cannot see them changing it from a 6 character set.
Oh and if you throw the original question into Google this OIA pops up from 2021
"Dear New Zealand Transport Agency,
What does NZTA intend to do when new vehicle registration plates hit ZZZ999 will the plates move to 7 characters or will the numbers be recycled."
The Answer was
"A move to a 7 alpha/numerical plate would require changes to the Land Transport (motor vehicle registration and licensing) Regulations 2011 see
– [3]r33 and [4]r34 where it’s currently limited to 6 & 5.
As there is currently still an extensive amount of plate combinations available, a review has not yet started to determine our next registration
plate format/series. Closer to the time of the current series concluding the requirements will be reviewed further."
https://fyi.org.nz/request/15755-number-plate-format