No, unless you have a same day onward domestic flight on NZ, in which case *G can use the domestic koru club.
That said, despite the rules I have successfully used the NZ domestic lounge when arriving as NZ business class pax, in order to use the shower. But it is possible those exceptions were thanks to my top NZ status (and the lounge bouncers knowing me).
Programs: TG ROP Gold, Lifetime OZ Diamond Plus, BA Gold
I've got an upcoming connection, international to domestic at AKL and would really like to get a shower before my connecting flight at the domestic lounge. Any idea of how long of a wait there is for the showers? I'll be at the domestic lounge probably about noon.