Former deputy prime minister Jim Anderton has died.
The former Alliance leader "passed away peacefully overnight at Cashmere View Hospital in Christchurch", his widow Carole said in a statement.
Funeral details will be announced in due course. He was two weeks short of his 80th birthday.
Former prime minister Helen Clark - who ran the country with Anderton as her deputy - said he was a "powerful advocate for the voiceless & marginalised & for a better, kinder, fairer New Zealand".
"He had huge leadership capacity & inspired me as a young Labour activist."
Megan Woods, who succeeded Anderton as Wigram MP in 2011 and is now Minister of Energy, said Anderton "hadn't been well for a while".
Prime Minister Jacinda Ardern said Anderton was a man of "huge integrity, huge compassion, a man who stood strongly for what he believed in and gave 40 years of service both in local government and central government".
Ardern said Anderton would be remembered for "many many things" including creating Kiwibank and after the Christchurch earthquakes ensuring there was a stadium available for people to enjoy sports.
"He will be sadly, sadly missed by the Labour movement and by all his friends and family."
Ardern remembered the first times she observed him when she was fresh in Parliament. She recalled the strength and conviction he brought to all of the issues he stood up for.
"He had such a sure way about him. He had such a strong sense of what was right, what was wrong. You never saw any hesitation in the way he worked."
Kiwibank would be part of his "significant legacy" to New Zealand.
Ardern recalled Anderton saying that "he never changed, his values never changed, things changed around him".
New Zealand had lost a man of integrity, compassion and dedication to public service, Ardern said earlier in a statement.
"He was a towering figure in the Labour movement for several decades. He will be remembered as someone who stood up for his principles and for the people he represented. His integrity during difficult times marked him out as a true leader.
"Jim's influence as president of the New Zealand Labour Party has lasted for decades. He built a powerful campaigning organisation, selected candidates who became Ministers and Prime Minister and he was an innovative fundraiser."
She described his work to establish the Alliance and Progressive Parties as "both difficult and trailblazing".
"He never gave up on the values of the Labour movement, and worked tirelessly to bring it back together through the years of the fifth Labour-led Government.
"Jim was also a loyal servant of the people of Sydenham and Wigram, serving as an MP from 1984 to 2011. He loved the people of Christchurch and his commitment continued beyond central government politics, including in recent years as Chair of the Stadium Trust and working to save the ChristChurch Cathedral.
"There are few figures in New Zealand politics like Jim Anderton. A man of deeply-held values and ideals, he was practical and compassionate. We mourn his loss, and extend our heartfelt sympathies to Jim's wife Carole, his family and friends."
She said he was first elected to public office in 1965 as a Manukau City Councillor and served local then central government for more than 40 years.
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'Strong-minded and determined politician'
National Party leader Bill English also passed on his condolences to the family and friends of Anderton.
"Jim Anderton was a strong-minded and determined politician who was admired by friend and foe alike. Jim knew New Zealand politics at every level, he was a strong advocate for people he believed needed representation and he was a critical figure in the evolution of MMP.
"Jim was also a highly respected leader in Christchurch. It was totally consistent with Jim's character that through his recent illness he continued to fight energetically for his views on the restoration of the ChristChurch Cathedral.
"On behalf of the National Party, I extend my sincerest condolences to the family and friends of Mr Anderton who supported him through his many years of service."
Green Party co-leader James Shaw said Anderton was "a great defender of the underdog".
"He stood up for New Zealanders hurt by the economic reforms of the 80s and 90s and devoted his public service to ensuring a fair deal for all. By forming first New Labour and then the Alliance, Jim also played a big part in ensuring greater proportional representation in our Parliament. His success in leading challenger parties paved the way for more diverse views to be given a voice in Parliament and government.
"Jim's work in establishing KiwiBank, supporting regional development and his latest role in the Christchurch rebuild demonstrate the breadth of public life in New Zealand that he touched. But our lasting memory of Jim will be of the stand that he took, consistently and passionately, in defending a fairer and more egalitarian way of life in New Zealand."
Christchurch mayor Lianne Dalziel said she was "truly saddened" by the news.
"I had the privilege of serving with him in Cabinet and I saw with my own eyes the extraordinary passion he brought to his portfolios. He breathed life into the regions believing as he did in the importance of their success. NZ simply could not succeed if the regions did not do well.
"He loved his city of Christchurch with equal passion and he was willing to serve us in so many ways well beyond his retirement from politics. I was pleased he was recognised in the Queens Birthday Honours List last year. It was a real tribute that the Governor-General came to Christchurch for the investiture.
"My sympathies go out to Carole and his family. Your support enabled Jim to serve us all in the way that he did and we are grateful. And to Jim I say thank you on behalf of our city of Christchurch for your dedication and service. May you now Rest In Peace."
Credit for Kiwibank, Super Fund
Former Finance Minister Sir Michael Cullen said he was very sad to hear of Anderton's passing and expressed his condolences for the family.
"Jim was one of the major figures of New Zealand politics in the 1970s to throughout the 2000s. His death is not unexpected, as he had been very ill for some time. He was a man of firm principles and was a very effective organiser in the late 1970s and early 1980s that helped the Labour Party get considerably stronger.
"He was very good to work with in (the Helen Clark) Government and was a very effective minister. He surprised a lot of people as Minister of Primary Industries in how he took up the cause of those in the primary sector."
Cullen said that Kiwibank was an important part of Anderton's legacy.
"But calling that his legacy is to underestimate Jim's contribution and the breadth of that contribution. It was a symbolic expression of what he thought Labour should continue to support and hadn't, obviously, in the late 1980s.
"To be honest I wasn't the greatest enthusiast about setting it up in the first place, but Jim was proved right in the global financial crisis when it became very clear that the Australian-owned banks would give prominence to Australian interests."
Cullen also gave Anderton credit for steering Labour back to becoming a "more recognisable centre-left party than it was by the late 1980s" and clearing up ideological confusion within the party.
"Jim was also the co-author of the NZ Superannuation Fund. In 1999 the Alliance didn't entirely agree with it and he and I negotiated a compromised solution that was the foundation of the Superfund. He deserves more credit for that than he is given."
A life in politics
Anderton was a former Labour MP who famously left the party after a falling out in 1989.
He went on to head the Alliance party and served as deputy prime minister from 1999 to 2002.
In 2010, he ran unsuccessfully for the mayoralty of Christchurch. The following year he retired from Parliament.
Anderton was credited with reviving the Labour Party organisation as party president from 1979, helping the party to victory in the 1984 election under leader David Lange.
Anderton quit the Labour Party in 1989 after refusing to support selling off the Bank of New Zealand. He famously remarked that he had not left the Labour Party, the Labour Party had left him.
He remained angry at Labour for many years, but put aside his differences to help Labour leader Helen Clark take power in 1999.
After leaving Labour in 1989 Anderton had founded the New Labour Party, which he said would stand for the social-democratic principles that Labour used to stand for.
New Labour merged with other left-wing parties to form the Alliance Party in 1991, which won two seats in the 1993 election, 13 seats in 1996, and became part of Clark's coalition government in 1999.
After his retirement, he campaigned to have Christ Church Cathedral rebuilt following its collapse in the 2011 earthquake.
Anderton was awarded the insignia of a Companion of the New Zealand Order of Merit in September last year. A small group of family and friends, former Prime Minister and Labour Party leader Helen Clark, and Mayor Lianne Dalziel, were at the ceremony.
Anderton appeared frail and was in a wheelchair at the ceremony. It was held at Nazareth House, where he was living.
Former National MP Philip Burdon said then that Anderton was "particularly frail" due to old age.
"He was really very frail and there was no way he could go to Wellington for the ceremony," Burdon said.
"It was a very nice and moving ceremony for someone the community has great respect for."