Getting past security is not guaranteed in Terminal 2; I've talked my way past it before by either telling them I needed to use the "international lounge" in T2, or presenting a domestic boarding pass that was printed by NZ. Worked both times. YMMV.

Actually getting into the MLL/KL would need either a Star Lounge compatible club membership, or a a Star Gold designation on a boarding pass (doesn't matter if domestic or not).