This was 2927mm, in December 1995 at the Cropp River, Waterfall gauge. This site holds most of NZ's rainfall records for various durations.
The daily values:
1 59
2 81
3 11.5
4 0
5 44
6 16
7 15.5
8 91.5
9 3
10 0
11 210
12 395.5
13 531.5
14 0
15 0
16 0
17 115
18 2.5
19 0
20 0
21 114
22 371.5
23 62.5
24 48.5
25 40
26 5
27 111
28 518.5
29 13
30 66.5
31 0
The next "best" effort was 2845mm at North Egmont, October 1998.