<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Spider:
It seems to me that flights to New Zealand (according to this MPM schedule) are via SYD/MEL since I don't know of any other way that CHC can be closer to Asia than AKL.</font>
No, you can route it anyway you like as long as the TPM (ticket passenger miles aka actual miles) don't exceed the MPM (maximum permitted miles). Excess TPM up to 25% of MPM may be ticketed for a surcharge.
For example, TIP-FCO-SIN-AKL is 12092 actual miles (TPM). That's less than the MPM of 13712 so no problem, no surcharge. TIP-FCO-NRT-SIN-AKL is 15383 miles, which is 12% over MPM, incurring a surcharge of 15% (MPM surcharges are always rounded up to the next multiple of 5%). On the other hand, tip-fco-sin-nrt-hkg-akl is 17697 or 29% over MPM, so it is just not allowed on this fare.