National Party leader Bill English has stepped down as Opposition leader, and, after 28 years as an MP, will quit politics entirely.
Mr English said he made the decision after some reflection during the Christmas break.
He said it was the "first time in a long time without political concerns."
Mr English made the announcement at a press conference in Parliament at 11:30am on Tuesday morning. He will remain the party's leader until 27 February. His caucus will decide on the replacement leader and deputy leader.
Mr English became emotional as he thanked his family, saying: "Your strength and tolerance has enabled my career."
Suspicion grew ahead of the announcement, when Mr English was 20 minutes late to National's weekly caucus meeting. His wife, Mary, and two sons Xavier and Rory were also spotted Parliament this morning.
They were by Mr English's side as he made the announcement.