Labour's caucus did not communicate effectively and parts of the party did not talk to each other, Labour leadership contender Andrew Little said tonight.
He was speaking to at least 600 party faithful in Wellington at the first of 14 hustings meetings for the four contenders.
"We need to fix the machine," he said.
He said he could not stand seeing power take advantage of the weak.
"When I see it it sticks in my craw."
He said there had never been "a more niggardly nasty National Government than the one we've got now".
Leadership contender Grant Robertson told the meeting Labour had to be a voice in the community every single day, not just when the party turned up asking for votes every three years.
Mr Robertson said the party had to not only be about fairness, but aspiration as well.
He wanted New Zealand kids to be the most connected in the world and the most confident, to top the PiSA (Programme for International Student Assessment) results in maths and English and to all have a second language.
Both Mr Little and Mr Robertson got a rowdy welcome as hometown candidates. Both mentioned the fact Parliament was tonight debating amendment to the Employment Relations Act which would weaken the ability to negotiate collective contracts.
Leadership contender Nanaia Mahuta said she knew a lot of people who would write her off in the contest.
She said she did not want her bid defined by her gender, culture, religion or sexual orientation but by Labour values of opportunity and aspiration.
Ms Mahuta said the challenge facing Labour was not just about leadership but how to build a team.
"We are stronger when we work together and are united."
Contender David Parker said Labour needed a unity of purpose and it had to decide what that was. It could not emphasise everything.
For him, the purpose should be "fairer economic outcomes for all".
Mr Parker said Labour had to represent the hopes and dreams of all working New Zealanders but they had changed. Many were self-employed or entrepreneurs and Labour had to represent them too.
Supporters of each candidate greeted the party faithful with leaflets.
Mr Robertson's leaflet said "new generation to win" and featured a picture of him and his preferred deputy, Jacinda Ardern.
Ms Mahuta's said "stronger together".
Mr Little's leaflet said: "This is our chance to make change for the good."
Mr Parker's said: "It's about a fair go for all New Zealanders."
Labour Party president Moira Coatsworth welcomed former MPs to the meeting, including former Prime Minister Sir Geoffrey Palmer.
• Nanaia Mahuta: In it to win, not just to be deputy
• Andrew Little: 'I can reach across the ideological divide'
• David Parker: Labour needs to act like a political party not a cult
• Grant Robertson: 'We've got to stop talking about ourselves'