The report concluded that in the long-term the port would have to move from its downtown location. The two preferred sites were the Firth of Thames and Manukau Harbour, according to the the member of the group, who did not want to be named.
A suggestion in April of a third option for a port at Muriwai - one of Auckland's wild west coast communities sitting in a regional park - has been dropped.
The Port Future Study was set up by Auckland Council following last year's battle over wharf extensions of about 96m in to the Waitemata Harbour for port use.
Port opponents won a historic victory after the High Court at Auckland ruled consents for the project were invalid.
Dr Rick Boven, the independent chairman of the group for the study, said he could not comment before the report went to the council's Auckland development committee next week.
He said some of the things said by Mr Peters and the study group member were not correct, but could not comment on what they were.
Mr Peters said a small wharf extensions "is not what Aucklanders want".
"They protested against any extension to the wharves and took court action which they won. Neither the port nor Auckland Council is listening to the people," Mr Peters said.
He said the study was delivered confidentially last week with recommendations being kept secret with proposals for the extension, and for a new port at either Manukau or the Firth of Thames.
"It is clear this was not a comprehensive study, it's a half-hearted approach serving particular interests, and not New Zealand's.
"The study did not consider how many ports this country needs, and did not look outside the Auckland region, to Northport or Tauranga. It did not consider the value to KiwiRail of an inland port nor the cost of congestion caused by trucks serving a port in the CBD.
"It surely did not consider the land the ports are using, and whether this is the most appropriate use given it is probably among the most valuable land in the country," he said.
Ports of Auckland will require a fresh resource consent for any future extension.
Auckland Mayoral candidate and Labour MP Phil Goff has said he would not allow the port to reclaim more of the harbour and wants to free up the "city's most valuable waterfront land" for residential and commercial buildings and public spaces.
There are mixed views among the mayoral candidates on the right with Vic Crone promising the look at relocating the port, saying its current downtown location is obsolete, John Palino arguing the business part of the port should be sold and Mark Thomas saying there were other priorities the council needed to deal with before looking at moving the port.
A Ports of Auckland spokesman said the company was not commenting to respect the confidentiality of the consensus working group.
