Former prime minister Mike Moore has been honoured as a giant on the world stage in a special tribute that has opened the year's first sitting day in Parliament.

Moore died on February 2, aged 71. He was New Zealand's 34th prime minister, serving for 59 days before the October 1990 general election.

Following Labour's defeat in that election, Moore served as Leader of the Opposition until the 1993 election, after which Helen Clark successfully challenged him for the Labour Party leadership.

Prime Minister Jacinda Ardern told the House today that she had the privilege of visiting Moore a few days before he died, and that Moore had used that visit to discuss the future of the country.

"Not one for small talk," Ardern said.

Moore had been a "working-class" prime minister.

"Where he saw wrong, he tried to right it. He deeply believed politics was ultimately about improving people's lives."

Ardern said that Moore had first joined the Labour Party when he was 15 and was a staunch union advocate.

"He taught everyone to aim for the start because that's what he did via books. Mike left school at the age of 15 for a job in the freezing works, but he was an avid reader.

"That he made his way to Parliament just eight years later is a testament to his work ethic, his dedication and his intellect."

Moore was first elected to the Auckland seat of Eden in 1972 when he was 23 years old.

Following his retirement from New Zealand politics, Moore was the Director-General of the World Trade Organisation from 1999 to 2002. He also held the post of New Zealand Ambassador to the United States from 2010 to 2015.

Ardern said Moore was emotive when discussing the history of New Zealand, and had said that a nation without history was like a man without a memory.

He had also cheekily tried to table a bill on constitutional change during his final speech to Parliament.

Ardern paid tribute to Moore's tenure at the WTO.

"There aren't many people who can say they led both New Zealand and the world, but Mike is of them ... he approached trade as a way to help those in need.

"He saw trade as an opportunity to lift people out of poverty and help developing countries to grow economically. It was a way to help the little guy."

National Party leader Simon Bridges also praised Moore's advocacy for free trade.

"It was Mike who first saw on the Labour side how free trade and being open to the world could benefit the working class – as he put it, how the workers could get their hands on the loot.

"He will be remembered for serving our country in the highest of international roles and putting our country on the map.

"He will be remembered for his belief in the potential of every New Zealander."

New Zealand First leader Winston Peters said that Moore had, as a young man, beaten cancer.

"He was given the gift of time and he used that gift to its fullest.

"Many New Zealanders will have fond memories of his political career – whether his championing of lamb burgers, his witty turn of phrase, his restless energy, or his passion for helping New Zealanders of all walks of life.

"I, for one, remember his cynical doubt about expert advice. Mike would say, 'Well we know it works in practice, let's see if it works in theory.'"

Peters said that Moore was much more than his achievements.

"It is the warm, passionate, funny, mischievous man that we will miss.

"Let us also pay special tribute to Mike's wife Yvonne and his family and send our thoughts and prayers to them."

Green Party co-leader Marama Davidson also referred to Yvonne in her tribute, saying that Moore had told his wife about his excitement when Ardern became Prime Minister because of what it would do for New Zealand's standing on the world stage.

Act Party leader David Seymour said Moore was short in stature.

"But he was a giant on the world stage."

Seymour lamented never meeting Moore, as he had left an indelible mark in defining New Zealand as a trading nation.

Moore suffered a stroke in 2015 and had been in declining health in recent years.

The Prime Minister's statement, which is normally delivered on the first day back and followed by a fiery debate, has been delayed until tomorrow so MPs could pay tribute to Moore in the House today.