Mr Brown and other councillors rejected a late plea from Warehouse founder and Kiwibank New Zealander of the Year Sir Stephen Tindall to halt reclamation until a full study of the economic, social and environmental effects was complete.
The council voted to start the study "sooner rather than later", but this does not stop the port company beginning its expansion plans.
A ports spokesman said last night work on two large wharf extensions nearly 100 m beyond the end of Bledisloe wharf would start in April. Work is expected to take 18 months.
Ports of Auckland obtained resource consent last December to extend the wharves.
The port company has said this is the first stage of a plan to reclaim 3ha of seabed between the wharf extensions over time.
The company will require a publicly notified resource consent for the reclamation.
Sir Stephen said politicians should use all their powers to stop this kind of "incremental approach".
Urban Auckland representative Julie Stout has produced images showing that the current view from the end of Queens Wharf, which extends to the Hauraki Gulf, would be narrowed to Devonport wharf once the Bledisloe wharf extensions are completed next year.
Mr Brown issued a statement after the vote seeking to downplay the implications of yesterday's decision.
The mayor said he did not expect the port to make any applications for reclamation until after the Unitary Plan became operative, expected to be next year. The ports spokesman confirmed this.
In the meantime, Mr Brown said, the council would undertake the wider study.
Tania Loveridge, of the Heart of the City business group, said it was critical for the council to find a way to put the planned Bledisloe Wharf extensions on hold until the study was completed.
"Our waterfront is too important to make incremental changes."
How they voted
For more generous rules
Mayor Len Brown, Deputy Mayor Penny Hulse, Arthur Anae, Cameron Brewer, Bill Cashmore, Linda Cooper, Alf Filipaina, Denise Krum, Calum Penrose, Dick Quax, Sharon Stewart, Penny Webster
For tougher rules
Chris Darby, Cathy Casey, Ross Clow, Chris Fletcher, Mike Lee, Liane Ngamane*, David Taipari*, Wayne Walker, John Watson, George Wood
*Maori Statutory Board members
Absent
Sir John Walker
* An earlier heading said reclamation was due to start in April. Wharf extension work will start in April.