Long-time Labour MP Ruth Dyson has revealed she will not be seeking re-election in 2020.
It will mean that after 27 years in Parliament, she'll bid the place goodbye to "pursue other challenges in my life".
"I truly love my job and adore my electorate and constituents," Ms Dyson said in a media statement.
"This has not been an easy decision to make, but it is one that has been made considerably easier by the fact that I am leaving at a time when Labour is strong and united, with a clear plan to deliver the policies that I have worked hard to develop."
But Ms Dyson promises that "there are no undisclosed reasons for this decision - it's just the right time."
Ms Dyson has been the MP for Port Hills since the boundary changes in 2008 saw the Banks Peninsula seat renamed. She was the MP for Banks Peninsula for three terms and had previously held the seat of Lyttelton - which she won to first enter Parliament in 1993.
Before that, she was the Labour Party President and played a role in the party's pushback against then-Finance Minister Roger Douglas' 'Rogernomics' reforms of the 1980s.
"Being the president was probably the biggest challenge that I ever took on because it was such a bad time for Labour," she said.
Ms Dyson helped in a series of campaigns including those of Labour MPs Fran Wilde and Kerry Burke.
The long-time MP was a Cabinet Minister under the Helen Clark government, holding portfolios of Social Development, Disability Issues and Associate Minister of Health.
She currently holds the role of Chief Government Whip, and hopes to keep it until she leaves Parliament in 18 months time.
"I certainly am unless Jacinda [Ardern] says she wants somebody else to do it ... but she hasn't mentioned that so far," she laughed.
"I'll never stop trying to improve things for people, that's sort of what drives me. So I'll just keep working with my ministerial colleagues and see how I go.
"But at the moment, I think they're all doing a fine job and they don't seem to need much pushing."
Ms Dyson had a key role in making New Zealand sign language an official language.
"Becoming the first ever Minister for Disability Issues was a real privilege and I think I got some good stuff done in my portfolios."
She worked extensively on homosexual law reform and last year her bill to ensure New Zealanders in retirement villages were eligible for rates rebates was finally passed.
Ms Dyson said it had been a privilege to serve as an MP in Christchurch for so long.
"I am not resigning from my role as Member of Parliament for Port Hills.
"I am staying in this role until the election next year and my constituents will remain my highest priority."