Committee for Auckland executive director Heather Shotter said the plans should be put on hold before the city goes down a road it cannot retreat from.
"We need answers to whether this is the best use of prime waterfront real estate, whether there are credible and affordable alternatives and what are the costs and benefits of releasing the port land for alternative use," she said.
Last week, ports chief executive Tony Gibson acknowledged that last year's plans to extend 283m into the harbour were unacceptable and hoped the scaled-back plans would lead to a harmonious relationship with Aucklanders.
The latest plans were sparked by a Herald campaign last year against further reclamation of the Waitemata Harbour. At the time Mr Gibson was focused on industrial action at the port and left the harbour debate to other staff.
Last night, he accused the committee of wanting to close the port and build a new port on virgin coastline - a "pointless act of environmental vandalism and an enormous waste of ratepayers' money".
"Why spend $4 billion on a new port when we can cheaply and easily make our existing port more productive?
"We have listened to Aucklanders and put forward a new proposal for just 6.6 hectares of reclamation, over 70 per cent less than before. It allows for the creation of 3ha of public waterfront [Captain Cook Wharf], and provides room for freight growth for decades," Mr Gibson said.
Mr Barnett said comments from the Committee for Auckland - whose members actually include the Ports of Auckland - represented an "elitist business view", not the views of most job-creating businesses in the city.
"The port is a strategic asset of incalculable value to the Auckland economy and employment," he said.
Heart of the City chief executive Alex Swney has cautioned Aucklanders over buying into the port company's "hysteria" when all it needed to do was improve its efficiencies and grow the business on the current footprint while the council determined the best long-term plan for the waterfront.
Barry Holton, deputy chairman of the Westhaven Marina Users Association, said the latest plans were almost as bad as last year's and significantly narrow the entrance to the harbour and affect tidal flows and wind patterns. "I represent a lot of harbour users and they are all totally against any narrowing of that harbour. Most of the people I talk to are pretty unhappy with what has already happened there," he said.
Ms Shotter said the committee would shortly release a report that she hoped would spark a discussion about marine matters affecting the "jewels in Auckland's crown" - the Waitemata, Manukau and Kaipara Harbours and the Hauraki Gulf.
The Committee for Auckland - comprising business and public sector groups - calls itself an "influential voice for all of Auckland".
Harbour Plans
Before:
Expand waterfront operations from 77ha to 99ha and 283m into the harbour. Dumped last year after a Herald campaign and public backlash.
Now:
Option 1: Expand Bledisloe Wharf 135m into the harbour for a 5.5ha expansion and keep Captain Cook Wharf for cargo.
Option 2: Expand Bledisloe Wharf 179m into the harbour for a 6.6ha expansion to free up Captain Cook Wharf for public use.
Harbour move
How far does Ports of Auckland plan to expand its waterfront operations into the Waitemata Harbour?
Last year, the port's communication manager, Catherine Etheredge, said Bledisloe Wharf would be extended by "approx 250m".
The company's latest briefing paper now puts the figure at 283m.
Asked to explain the difference, the company's new communication manager, Matt Ball, said he was not sure where the 250m came from and concluded it was someone else's guesstimate.
"In any case, you can take all our current measurements as 100 per cent to the metre," he said.
The company's latest, scaled-back plans are to extend Bledisloe Wharf by 135m or 179m.
