Former Labour Party leader David Cunliffe will retire from politics at the 2017 election, but says he has not been forced out of Parliament.
Labour leader Andrew Little today announced Mr Cunliffe would not be seeking re-election.
"He is joining the leadership team of Auckland-based management consultancy Stakeholder Strategies Ltd, a leading strategy and organisation consulting firm that provides advice on commercial, economic and environmental issues," Mr Little said.
He said Mr Cunliffe planned to step down sometime next year and wanted to avoid triggering a by-election.
He had made a "strong contribution" to Labour as the MP for New Lynn since 1999 and as a former leader and finance spokesperson.
Read about David Cunliffe's political career here
Mr Cunliffe led Labour to its defeat in the 2014 general election, the party's worst electoral performance since 1922.
He resigned as leader after the election but contested the subsequent leadership race before throwing his weight behind Mr Little.
At the time, fellow former leader David Shearer questioned Mr Cunliffe's motivation for withdrawing from the leadership race, saying he would end up undermining whoever won.
Fellow MPs also accused him of failing to support then-Labour leader Phil Goff during the 2011 election campaign, an accusation Mr Cunliffe rejected.
Mr Cunliffe was a Cabinet minister in the most recent Labour government, holding the portfolios of health, information and communications technology and immigration.
'I've had a great run in politics'
Mr Cunliffe said he made the decision himself, and was not forced out by Mr Little.
"A great opportunity has come my way. I've got options and I'm looking forward to taking them.
Asked about his greatest challenge since entering Parliament in 1999, Mr Cunliffe said challenges "come and go".
"Look, I've had a great run in politics, it's a rollercoaster as we all know, but it's an opportunity at the end of the day to make a difference for New Zealanders. It's not about us, it's about them and improving their lives and God knows they need help at the moment."
Mr Cunliffe said one of his biggest regrets was the impact Kim Dotcom and the Internet Party had on the result of the 2014 election.
"A large German billionaire that came from nowhere and swung like a wrecking ball through New Zealand politics. We tried to stay well away from him, but undoubtedly he was a one-man turnout machine for marginal National voters."
Mr Little said he did not want to go over the old ground of accusations of disloyalty.
"I'm not here to talk about things that happened a long time ago, David has made his decision, I have made the announcement today and so we know think about the next steps, but understand David continues to be well-respected and a good friend of mine."