Being the now standardized metric cable sizes, that sounds pretty much the same as the U.K. 5 or 6A lighting circuits can be on 1 or 1.5 sq mm cables. Many smaller old properties have only one lighting circuit, although two is the norm now that people have more in the way of wall lights, porch lights, etc. Most of Continental Europe specifies 1.5 sq. mm as the minimum cable size though.
Do you know when NZ adopted metric size cables?
