Whatever... QFA however had to take avoiding action that involved a left turn to 'miss' ANZ. According to your comments it can't have been due to a TCAS RA, visual sighting perhaps or due to cues provided by TCAS (TA?)... What I do know is that they missed by not very much at all!!
The thing that concerns me most was that at 3000' QFA was above the minimum radar vectoring altitude and yet received a GPWS alert. The highest terrain in his vicinity was the top of Rangitoto Island (800' or there abouts) and as I work on this sector at present I will have to modify the way I operate!
As a footnote, I know that at Wellington the MRVA is also 3000' but rarely do they descend traffic below 4000' in IMC (especially jets) over terrain because they have been caught out there in the past with GPWS alerts.
TP