[BirdieNZ]

Auckland specifically has a declining population, although it may change this year with immigration returning to pre-Covid levels. Aucklanders often move out of Auckland either overseas or to cheaper cities, when the economy slows, in a mild version of a boom bust cycle. Usually immigration offsets this but it hasn't quite picked up to the previous levels yet.

NZ as a whole doesn't have a declining population, and Auckland usually does not.