Asked if successful, would he want his deputy elected next Tuesday, he said it was not a subject he had traversed but if he was elected, "I'll be wanting to have a conversation with our current deputy to see how he feels and I won't be making any comments until I have had a good chat with him".
Mr Cunliffe, Mr Robertson and Mr Jones have been hitting the phones for the past few days after speaking to 3,750 members at 12 hustings meetings. Under new rules, members have a 40 per cent say and affiliated unions a 20 per cent say in the leadership, with the caucus having 40 per cent.
Mr Cunliffe said the highlight of the campaign had been to see the sense of optimism and hope on the face of Labour members at the meetings.
"It has been extraordinary and I feel a huge obligation to them, whoever is elected, that we all pack down together and do the very best we can to uphold their hopes and dreams and win in 2014."
He said the three candidates had become closer through the process "and I think it provides a good basis going forward".
Mr Robertson said the expectation created by opinion polls was that he was an underdog in the contest "but I still think I am very much in this contest.
"This is a vote of the members, affiliates and the caucus and across those groups I've got strong support."
He had not yet thought about the deputy's position if he won.
He said the highlight of the campaign was seeing members revitalised at the roadshows.
"This has been a good process," he said. "If I don't win - and I'm very optimistic that I will - I will be expecting everybody who has supported me to get in behind the new leader."
Mr Jones would not say who he thought would win but said: "I'm fighting this until the final hour."
One of the highlights was the large number of people who turned up and rejoined Labour, especially in the North. "They said 'we've come back, we've heard you on the radio, you're one of ours, and we owe you big time' and that touched me big time because I had hardly been a stellar performer in earlier times."
Another highlight was going to Blackball to be reminded of the simple but tumultuous times the party had been born from.
Former leader David Shearer resigned after losing the confidence of his key caucus backers, who are now supporting Mr Robertson.
Membership has increased by 20 per cent during the campaign but many were renewals or lapsed members returning, Labour general secretary Tim Barnett said.
What the experts say
John Armstrong, political correspondent:
Labour's first road-test of its new rules governing the election of a leader has been a success - so far at least.
Helped considerably by the high calibre of the three contenders for the party's top job plus a high degree of discipline on their part, the process has given Labour its most sustained period of positive media coverage since the Helen Clark era. It has also provided the space for a much-needed, though still limited, party-wide debate on Labour's direction and how that squares with the party's traditional principles.
The big test, however, will be whether all the party's sectors and factions will live with the result. The caucus will be unhappy if David Cunliffe wins. The wider party will have very mixed feelings if Grant Robertson is the victor.
The whole party will be in a state of shock if Shane Jones triumphs.
Whatever, with Labour's annual conference just around the corner, the whole party must unite around its new leader.
The time has come for Labour to stop looking inwards and focus outwards.
With the Christchurch East byelection beckoning, talking with New Zealanders - rather than at them - would be a good place for the new leader to start.
Audrey Young, political editor:
David Cunliffe may be the winner tomorrow but Shane Jones won the campaign because he did more with it.
He has propelled himself from the wop-wops of the party into relevancy, a safe list place, and a potential future contender for the job.
He brought a dose of reality to the contest, pointing out the party's failings, without offending it. In the process he went a long way to redeeming himself. If the new leader is smart, he will keep Jones close but give him licence to occasionally don his maverick cloak.
Grant Robertson performed on the hustings as he has done in the House, with confidence, competence, and occasional brilliance. He has failed to project himself as a natural winner.
Cunliffe's campaign was impressive: he had a dedicated team behind him, it was smart and well-organised. Occasionally he leaned dangerously closer to pantomime than politics.
The one worry was his sacking aide Jenny Michie after TV3 replayed a two-week-old clip of her saying something perfectly reasonable about Robertson's gayness (it being an issue for some people, not for her). Justified as taking the moral high ground, it was also a complete overreaction.
What was missing from the campaign was real pressure. They were all literally preaching to the converted. The pressure starts tomorrow.
