"She epitomised the best of New Zealand values. When she saw others in need, she offered to help. When she saw injustice she strove to correct it. When she saw the opportunity to fight for progressive ideals, she climbed in boots and all, compromisingly, relentlessly, and with one goal - to make positive change."
Prime Minister John Key said Kelly "didn't come from my side of the political fence".
"There were occasions that I simply didn't agree with her," Key said, in particular during the dispute over the Hobbit films.
"Sometimes the forceful way Helen Kelly made her arguments frustrated me, but she also had my enormous respect. She was passionate, she was tenacious, she was articulate, she was intelligent, and she was pragmatic."
Kelly had a great deal more to give, Key said, and it was no secret she was considering running for Parliament before her illness.
"She would have enjoyed I think the opportunity to debate in this House those values and principles that she held so deeply, and we would have enjoyed debating with her.
"But the truth is that Helen Kelly didn't need an office in the Beehive to make a difference to New Zealand. She made that all too easily through the capacity of her arguments, and the way she articulated them."
New Zealand First leader Winston Peters said Kelly was a "standout New Zealander" who was a person of true character and integrity.
It could be said that Kelly "put unionism on a new level", Peters said, and a good society needed that representation.
"We were a better country for witnessing her professional life, and a lesser country for her departure.
"On these occasions it is so common for speakers to rise and use the most effusive and laudatory language. But in Helen Kelly's particular case, what is said today has a very special significance."
Green MP Denise Roche said Helen Kelly was a remarkable woman and said she would have shone as a Member of Parliament.
"We sometimes referred to Helen as the union movements answer to Xena, Warrior Princess because of her staunch advocacy, her willingness to enter the fray and her ability to win a fight - and her cute dimples."
She said a fitting memorial to Helen Kelly would be an overhaul of New Zealand's industrial relations laws - "a health and safety law that actually protects farmer workers, a reversal of the Hobbit law, a living wage for all ordinary New Zealanders, a law that enables New Zealanders to join a union without fear of retribution and the ability to organise for better working conditions and for someone to be held responsible for the Pike River Mine tragedy and for the bodies of those men in that mine to be returned to their families."
Most speakers were supported in a waiata after their tributes. Roche sang Bread and Roses.
Kelly backed industrial action by some of those working on the Hobbit in New Zealand in 2010 as part of the fight against changes the National Government was making to the employment status of film workers, saying it was selling out workers' rights to appease US film-makers.
