Not the most informative warning. No mention of when or how severe likely!
FWIW the earthquake occurred at 12:24:51 this afternoon our time, and any tsunami will take 12 - 13 hours or so to reach northern NZ. So a few hours yet before need to worry too much. More info here if interested ww.tsunami.gov. Prelim est 0.3m - 1m tsunami in NZ.
Travel times below from https://www.ncei.noaa.gov/maps/ttt_coastal_locations/
CD could easily have got this info with a few minutes work.