Apex domains cannot have CNAME records.
Question and response
Question
dig internet.co.nz. NS
Answer
internet.co.nz. 3 NS ns1.iconz.co.nz.
internet.co.nz. 3 NS ns2.iconz.co.nz.
Authority
The response has no authority records.
Additional
ns1.iconz.co.nz. 3 A 210.48.48.210
ns2.iconz.co.nz. 3 A 115.126.128.55
ns1.iconz.co.nz. 3 AAAA 2405:6000:2:4:0:0:0:4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0