John Tamihere has called a press conference in West Auckland tomorrow at 9.30am.
The Waipareira Trust chief executive has been setting himself up to challenge Phil Goff for the mayoralty at the local body elections on October 12.
Last October, he told the Herald he was "still crunching the numbers" before making an announcement in the New Year.
Tamihere is a high-profile - and often controversial - figure. A lawyer by training, he led Waipareira Trust from 1994, then served as a Labour MP from 1999 with a role as a Cabinet minister after the 2002 election.
He lost his seat in 2005 after inflammatory comments he made about colleagues, had a spell as a talkback radio host and returned to run Waipareira Trust.
Tamihere said if he stood for the mayoralty he would focus on social and affordable housing and have a running mate for deputy.