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.
...
domain_datelastmodified: 2014-07-28T13:54:33+12:00
...
ns_name_01: ns1.spark.co.nz
ns_name_02: ns2.spark.co.nz
ns_name_03: ns3.spark.co.nz


$ whois spark.co.nz
...
domain_datelastmodified: 2014-06-10T10:08:28+12:00
...
ns_name_01: ish4.telecom.co.nz
ns_name_02: ish5.telecom.co.nz

No glue records, so no way to resolve the NS IP's

FYI:
ish4.telecom.co.nz. A 146.171.13.195
ish5.telecom.co.nz. A 146.171.13.194

ns1.spark.co.nz. A 146.171.13.195
ns2.spark.co.nz. A 146.171.247.25
ns3.spark.co.nz. A 146.171.13.194