Steven Joyce is to retire from Parliament.
"I have had a wonderful time in this place over the last nearly 10 years including nine years as a Minister, and have been privileged to be able to make a real contribution to the development of our country," the National MP said.
"With the recent change of National Party leadership I have had the opportunity to consider again what I would like to do over the next several years."
Simon Bridges' election as National leader had led to his decision to retire.
The 54-year-old will return to the commercial sector.
"With the recent change of National Party leadership I have had the opportunity to consider again what I would like to do over the next several years.
"Simon has made a very positive proposal to me to stay and contribute as a senior member of the team on the front bench with a choice of portfolio.
"However I feel that it is time for him to get a new team around him to take National forward and win in 2020 and then govern again for the benefit of all New Zealanders."
Newstalk ZB political editor Barry Soper says he's taken the National Party from strength to strength as its campaign manager.
"But in one way he's, I guess, let Simon Bridges off the hook [as] he's now free to choose somebody else in that finance role."
Joyce entered Parliament in 2008 and went straight into a role as Cabinet Minister under then Prime Minister John Key. He had offered to assist Bridges and National.
Hi all. Today I have announced my retirement from Parliament. I have had a wonderful time in this place over nearly ten years, including nine as a Minister. My plan is to return to commercial life and to focus on being a good Dad for Tommy and Amelia.— Steven Joyce (@stevenljoyce) March 6, 2018
Joyce has led the party's general election campaigns since 2005.
"I have led the National Party's general election campaign five times as campaign chair and in four of those for John Key and Bill English, we achieved a Party Vote in excess of 44 per cent, the only time it has happened under MMP.
"And it was an honour to be Bill English's Associate Minister of Finance for eight years before presenting my own Budget in 2017, which continued building the platform for future economic growth and focused on boosting incomes for low- and middle-income earners.
"My plan now is to return to commercial life and seek new challenges and also to focus on being a good Dad to Tommy and Amelia."
Joyce was dubbed the "Minister of Everything" and "Super Minister" after he created the Ministry of Business, Innovation and Employment. He was Minister of Economic Development before becoming Finance Minister in 2016 after Key left.
Joyce told reporters he had been lucky to have a busy nine years and hoped he had made a contribution to the development of the county.
Joyce said he met Bridges in Tauranga this morning to tell him of his decision.
He denied it was a response to Bridges saying he would not get the finance portfolio, saying it was a personal decision.
Joyce said Bridges had not offered finance but had offered him a choice of other roles on the front bench.
He said he was not sure if he would have stayed even if he did retain the finance portfolio.
Joyce said believed Bridges would "acquit himself well" as National leader.
He said he had no regrets about standing for the leadership - and said he would offer whatever help Bridges asked for.
Joyce denied his decision to quit was a direct response to losing the leadership bid.
"I think if I was in a petulant mood I'd have gone to the backbenches and grown a beard," he said.
"The thing that made me stand for the leadership was I'm really passionate about helping New Zealanders work hard and get ahead."
Joyce said it was not easy to turn his back on that but at some point it had to be done.
He said his career had featured some interesting moments - including the sex toy thrown at him at Waitangi - but said it had been "a blast."
Asked if he regretted claiming Labour had an $11 billion hole in its numbers during last year's election campaign he said "absolutely not."
Asked for his parting words to Finance Minister Grant Robertson, Joyce said he would urge him not to forget the businesses working hard around the country.
Joyce said his crowning achievements included the national broadband rollout, saying it would help New Zealand businesses compete internationally.
His only regret was having Labour repeal National's tax cuts, saying it would mean workers on the average wage paying the top tax rate.