Long-serving Labour MP Clayton Cosgrove is to retire from politics at next year's election.
Mr Cosgrove, who is 46, has been an MP since 1999 and held several ministerial posts, including Minister of Immigration, in Helen Clark's government.
He said he wanted to take on new challenges and opportunities and was looking for opportunities in the business sector. He did not rule out resigning his seat before the election.
Mr Cosgrove was MP for Waimakariri until his defeat in the 2011 election, and has since been a list MP.
Next on the Labour list is former MP Maryan Street - meaning she would replace Mr Cosgrove if he leaves Parliament before the next election.
Ms Street isn't giving media interviews, but in a public statement on her Facebook page she wrote:
"Yes I am next on the list, and no, there is no decision I have to make at this moment - I will cross that bridge when I come to it," she wrote.
"As many of you know, I have remained very active since leaving Parliament on one significant policy issue - the legal frameworks around the issue of assisted dying have occupied much of my attention.
There is currently a petition in my name with nearly 9000 signatures before the Health Select Committee, seeking greater end of life choices through physician-assisted dying."