"More Direct Route" has ALWAYS been the rule for Star awards using UA miles. They are enforcing it tightly recently. So SYD is UA if there are seats.

To BNE TG or NZ are acceptable, or for PER Air NZ is the only option. ADL is not permissible as you can only fly there on SQ via SE Asia and that is not allowed.

The easy way around it (for SYD or MEL) is to request the one legal "stopover" to be in AKL.