Phil Goff will confirm his bid to become mayor of Auckland on Sunday.
The senior Labour MP and widely-tipped front-runner for Auckland's top job says "an announcement" will be made at an invite-only function at Westhaven Marina.
Councillors and local board members are on the 1:30pm guest list and while it's understood Goff will stop short of launching his actual election campaign - remaining MP for Mount Roskill - he will formally announce his decision to stand for the mayoralty and replace Len Brown in next October's Local Government elections.
Goff declined to discuss the announcement but finally appears ready to put an end to months of speculation, exactly two weeks since Brown confirmed he would not seek a third term in office.
Brown took himself out of the running a fortnight ago, admitting the fallout from the extra-marital sex scandal which rocked his mayoralty in 2013 had inflicted too much damage to have a chance of re-election.
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.