"We as a caucus have to come together as a team ... I welcome all popular caucus members along."
He said his leadership campaign was the start of a "long-term project ... to rebuild".
"I'm taking this very, very seriously."
Ms Ardern said she was honoured to have been asked by Mr Robertson to be on his ticket.
"I think our ticket together is about bringing in a broad range of support from across the party.
"We're trying to make sure we have a story that appeals to a wider range of New Zealanders."
Her support for Mr Robertson wasn't a job application for the role of deputy leader to any Labour leader, she said.
"This is not about me trialing for deputy generally. I'm performing this role specifically for Grant for this campaign.
"Ultimately that will be decided by caucus."
Mr Robertson said a new generation of Labour needed to be committed to five things: listening; being prepared to face challenges of the future like climate change; being committed to workers, small business and entrepreneurs; focusing on education, housing and health; and being loyal to Labour values.
"My leadership will be characterised by looking forward and looking outwards," he said.
'We've got to be talking to New Zealanders'
Appearing on TVNZ's Q&A this morning, Mr Robertson said Labour needed to review all of its policies and be clear and true to the party's values.
"There's a group of New Zealanders who feel that we're not speaking to them about their lives. They're all sorts of people from different backgrounds."
"What we've got to be talking to New Zealanders about is what kind of New Zealand they want to be a part of.
"Work's changed and we've got to get alongside the courier drivers and the people who are starting the new small businesses and say to them, 'we back you as well'," Mr Robertson said.
"We've got to have clear policies that speak to people's lives. When we do that, we'll come together around that.
"If people step outside of it, there have to be consequences."
David Parker said politics was a mixture of people, policy and presentation. "We got that mix wrong obviously."
"New Zealanders are not going to come back to Labour until they've got confidence in us. For them to have confidence in us we have to express our unifying purpose across the party that they agree with which serves their purpose.
"For me, that's taking Labour party primarily back to the interests of working New Zealanders.
"We were a party born of working people for working people and I think that people look at the Labour party now and they see that we're more there for the vulnerable primarily now.
"I think that the way to protect the vulnerable is to actually take working New Zealanders with you
Too many people at the election were ashamed to admit that they were voting Labour, Mr Parker said. He said he would lead by looking outwards, not inwards.
Nanaia Mahuta said some of Labour's policies, including a capital gains tax, no longer spoke to the broader constituency of working people.
Labour needed to use its diversity and skill-set from across its caucus to ensure the party was focussed its core objectives, she said.
Andrew Little said New Zealanders were looking to politicians to find solutions to their problems.
"They didn't hear solutions from us to their problems.
"I think people are wanting an environment where we've come out of difficult economic circumstances. We know people are struggling.
"They wanted to hear something that was going to give them a bit of stability, a bit of confidence about the future and that's not what they heard from us.
"My general summary is that we put a lot of things out there that in the end, scared a lot of people off," Mr Little said.
"If we as the Labour party care about ensuring there is a fair society, less inequality, dealing with child poverty, we need to be in government.
"We put a bunch of our things out there asking people to vote for us that turned people off us. We've got to be honest about that."
- additional reporting Brendan Manning
