I did have someone with greater search skills in Geni look for me 1956-1965
and he found Nothing....most odd as they shown as a married couple in Electoral Rolls 1960
Moderator edit: comment removed. What needs to be mentioned perhaps is that ... after 1956 (the extent of the NZSG Marriages available on cd), there is the option to refer to microfiche records of NZ Marriages up to the year 1990 * . This can be done usually at larger libraries in New Zealand (and some other repositories - a few of which include Australia.) That requires a physical visit though ... but you might find a New Zealand libarary online whose genealogy section could help with a "look-up" of the information.
In the case of the marriage you seek, the years to be covered are few ... e.g. 1956 to
**1960 1963.
If they are registered genealogists and have access to full database on a paid sub.
(I think).....

.... that information is not entirely correct re: "registered genealogists" :
~ Lu
added:
* (checking for exact year) ....
but is at least to 1980.Amended date > 1990 > is now in text above ^ [source: NatLib NZ ]
Further amended
** ... year to read as
1963 :