The Northland port company chair Sir John Goulter is urging the Auckland Council to think again about the freight potential of Northport and Port of Tauranga.
The Auckland Development Committee's passed its Port Future study on to the incoming council, to look at growth problems faced by Ports of Auckland.
Sir John said the study took an overly narrow view, and contained errors that led it to dismiss Marsden Point and Tauranga as viable solutions.
He said the two ports could never assume Auckland's total freight task, but the load could be unbundled and shared, and that had not been properly explored.
The Port Future study overlooked Northport's consented expansion plans which will give it a hardstand area of 50ha and 1.4km of berthage, he said.
Sir John said the irony was that Aucklanders didn't want their port to grow - while Northland people would welcome the opportunities that expansion would bring.