Its not a secret data release but you won't find it on economic calendars.

Due at 0300 GMT on 21 April 2022 is the RBNZ’s preferred Sectoral Factor Model measure of core inflation.

  • the most recent read (that for Q4 2021) was 3.2%
  • the RBNZ target band for core inflation is 1 - 3%
  • the data for Q1, 2022, is released today and its likely to show core inflation even higher than the 3.2% last time

The latest data is for Q4 2021, today we'll get that for Q1 2022:

rbnz q4 2021 sectoral inflation