Kia Ora. :)
Until 1999, New Zealand's bank notes were printed on paper made from cotton. On 3rd May 1999, the Reserve Bank started circulating polymer (plastic) bank notes. The main reasons to change to polymer were:
* The average polymer note lasts four times as long as a paper note. That keeps the cost of producing money down;
* Polymer notes are stronger and non-porous, so they do not get as dirty as paper; and
* It is easier to make secure a polymer than a paper note, thus deterring forgers.
How's your son faring in Auckland, jan?