A bit late - a new 48-hour record for rainfall in NZ was set at the Cropp Waterfall site in Westland (975m ASL) during a major rain event 25-27 March, which caused a lot of damage, including the washout of the bridge over the Waiho river at Franz Josef. Cropp recorded 1086.5mm from 09:12 on the 25th to the same time on the 27th, breaking its own record of 1061mm on 1-3 January 2013.
https://www.stuff.co.nz/national/112018973/vital-waiho-river-bridge-reopens-reconnecting-recovering-west-coast
Average annual rainfall at Cropp (1982-2018) was 11280mm, and there are certainly wetter spots that haven't been measured properly yet.