The Auckland area may have provided a quarter of all All Blacks,  but it's over a third of NZ's population.... so maybe under-represented?
There was no 'indigenous' NZ population.... the Maori arrived a 1000 years ago, or whatever, .... before, there was nobody. The white population dates only from about the 1840's. 

I suppose it could be said, tongue in cheek, that the British brought Football, cricket and rugby to its colonies etc... The Antipodies, South Asia and indeed SA!!