Phil Goff has announced his impending retirement from politics, ending one of New Zealand's longest political careers.
Mr Goff, currently Auckland's mayor, was first elected to parliament in 1981, becoming a senior minister in Helen Clark's government and succeeding Ms Clark as Labour leader when she lost office.
"It's more than 40 years since I was first elected to office as MP for Roskill in 1981," Mr Goff said.
"I believe it's time to pass the baton to a new generation of leadership."
Mr Goff will leave at the end of his mayoral term later this year.
Prime Minister Jacinda Ardern paid tribute to her former employer.
"As my first boss in politics, I can personally attest to the fact that Phil Goff is a man of great integrity, who has always focused on service to New Zealand," he said.
The 68-year-old was no stranger to Australia as foreign affairs minister for six years under Ms Clark.
He stayed on after losing the 2011 election during the height of Sir John Key's popularity, leaving parliament to win the Auckland mayoralty in 2016.
His departure will trigger a hotly-contested race for mayor in October's local government elections.
Labour is set to back Efeso Collins against controversial hospitality figure Leo Molloy, a major critic of Ms Ardern's COVID-19 policies.