Brown's decision has been greeted with relief by council members, who say they can focus on milestone decisions for Auckland's future instead, while his support from the left and centre are expected to be gobbled up by Goff, a former Labour Party leader.
It is understood David Lewis, a former chief press secretary to Prime Minister Helen Clark and adviser to Brown at the last two elections, will be Goff's campaign manager.
With the relationship between Government and Auckland Council becoming strained under Brown on a number of topics, including the key issues of housing and transport, Prime Minister John Key has previously said he would be prepared to work with Goff as another left-of-centre Auckland mayor.
However, it remains to be seen whether a heavyweight candidate from the right can still be found following new ticket, Auckland Future, getting the backing of the Key-led National Party.
Earlier this week career businesswoman and Xero New Zealand managing director, Victoria Crone, announced she was also considering a tilt at the mayoralty.
Former Green Party member David Hay also has confirmed he is considering a tilt at the mayoralty.
• An earlier version of the poll beside this article omitted the names of declared candidates: Stephen Berry, Penny Bright, David Rankin and Mark Thomas.