Labour MP Phil Goff is expected to throw his hat in the ring for the Auckland City mayoralty today.
Mr Goff has called city councillors and media together for a major announcement at Auckland's Westhaven Marina.
It is expected he will confirm long-running speculation he will contest the role in next year's local body elections.
Mr Goff is believed to have hired incumbent mayor Len Brown and Helen Clark's former spin doctor, David Lewis, for his campaign.
Brown announced this month he will not be seeking re-election.
Mr Goff is the member for the Auckland electorate of Mt Roskill, and has served as a cabinet minister and led Labour to defeat at the 2011 general election.
He has said if his bid for the mayoralty is successful, he will resign as an MP, meaning Labour will have to find a replacement to contest a by-election in the electorate he has held since 1981.