FYI - looks like there is an issue with telecom authoritative DNS.
Short version: it's currently broken.
Long version: there is a whois/NS loop
$ whois telecom.co.nz.
$ whois spark.co.nz
No glue records, so no way to resolve the NS IP's
ish4.telecom.co.nz. A 22.214.171.124
ish5.telecom.co.nz. A 126.96.36.199
ns1.spark.co.nz. A 188.8.131.52
ns2.spark.co.nz. A 184.108.40.206
ns3.spark.co.nz. A 220.127.116.11