Mr Peters, who may hold the balance of power after the election, would say only that the voters will decide the next Prime Minister.
He said the so-called rock star economy was actually on the rocks.
"If this is as good as it gets, then it doesn't matter who the next Prime Minister is.
"A vote for New Zealand First is a vote for New Zealand First and not for any other party."
The Campbell Live debate was more of a timid discussion around the dinner table at Auckland's Grand Harbour Restaurant, as subjects traversed the Maori seats, the minimum wage, and tax policy.
Each leader was asked who they wanted to be the next PM. Mr Craig, United Future's Peter Dunne and Act's Jamie Whyte all said Mr Key, while Ms Harre and Greens co-leader Metiria Turei opted for Labour's David Cunliffe.
Maori Party co-leader Te Ururoa Flavell said he was not fussed and could work with either, as long as the relationship helped Maori.
Mr Craig took a dig at Mr Peters: "Every single person gave an honest and direct answer except one ... People are looking for a safe pair of hands, and for people they can trust."
Mr Peters retorted that the Conservatives had simply stolen all his policies. "Imitation is the sincerest form of flattery."
After the dinner, Mr Peters said it would be irresponsible to lay his cards on the table without "all the facts".
"This has been the most astonishing campaign ... and I believe in the next 16 days there's a lot more to come yet."
He did not think he would lose any votes over it.
Nicky Hager's book Dirty Politics was mentioned only when Mr Peters said he believed the "explosive" claims in it were true.
"The left wing didn't write the emails. The National Party did. We need to restore political integrity."
The parties argued over the Maori seats, which Mr Flavell said was a hot topic every election, when issues of "kai on the table", tertiary education and home insulation were more important.
Mr Peters accused Mana Party leader Hone Harawira of destroying the Maori seats' integrity in a "deal with the German [Internet Party found Kim Dotcom] who should not be here in the first place".
The dinner started with the leaders talking about what they thought was the most important issue.
Mrs Turei said it was child poverty, while Ms Harre said it was young people and helping them into education, training, or work. Mr Dunne said it was about helping families and parents, while Dr Whyte said it was a dynamic economy, fuelled by a low company tax rate to drive investment and productivity.
Mr Flavell said family violence was a big issue in three Maori electorates, and Whanau Ora, the health, education and social services programme with a Maori focus, was his focus.
The leaders took a moment to giggle at Dr Whyte, who was embarrassed a few weeks ago when he revealed he did not know what Whanau Ora was.
Both parties stretch truth over new taxes
As the tax debate heats up Prime Minister John Key says a Labour-Greens Government would hit New Zealanders with five new taxes, prompting Labour to hit back with the claim that National had introduced at least 15 new taxes in the past six years.
As usual the truth is being stretched as both parties have portrayed tax increases as new taxes.
Four of the claimed new Labour-Greens taxes stack up.
The capital gains tax, increased top tax rates and water tax ring true.
The first two are headline Labour policies while Labour also has a policy for a resource rental on large water takes for irrigation, "at a fair and affordable price".
Labour Leader David Cunliffe yesterday ruled out a carbon tax but the Greens' policy is for a carbon tax set at $25 a tonne.
A Labour spokesman yesterday said the party had no plans for a regional fuel tax.
National's Economic Development Minister, Steven Joyce, doesn't dispute that any of the 15 charges named by Labour happened - except the fringe benefit tax expansion which he said was abandoned.
However about half of the remaining "taxes" were user fees that applied to a limited number of New Zealanders, he said.
- Adam Bennett
Our views
John Armstrong, political correspondent
Winner: Te Ururoa Flavell
The measure of who won the debate had to be different by virtue of the venue, a Chinese restaurant. Whereas some leaders behaved as if they were addressing a 500-seat corporate lunch, the Maori Party's Te Ururoa Flavell was the perfect dinner party guest - polite, relaxed, convivial, engaging and, above all, quietly amusing. He made the points he wanted to make with more telling effect than some others who had forgotten to change out of their ideological strait-jackets. Exempt from that classification were Act's Jamie Whyte - who wisely did not take the event or himself too seriously - and Winston Peters, who looked like he had ensconced himself in his seat with the intention of staying long into the evening. The Conservative Party leader Colin Craig had obviously turned up in order to get the better of Peters, his main rival, face-to-face. It seemed only a matter of time before one invited the other to settle things outside in a not so Christian manner.
Audrey Young, political editor
Winner: Jamie Whyte
The idea of setting up a dinner debate with seven political rivals in a Chinese restaurant was not without risk. A food fight was never among them; formality and awkwardness could have ruined the night. But the intimacy of the table and John Campbell's bonhomie made it special. After a guarded start, Winston Peters had the assured air of someone who knows he'll be back. Those with the most to gain were Conservative Colin Craig, yet to crack 5 per cent in any poll, and Act's Jamie Whyte who stands on the cusp of oblivion. Whyte seized every opportunity to fight his cause of smaller Government. It might not save his party but he was the winner.
Toby Manhire, columnist
Winners: Winston Peters and Metiria Turei
After the fisticuffs of Christchurch, the dinner-party format was a welcome relief: civilised, jolly, informative - fortune cookies, even. All the pretenders scrubbed up well. Winston seemed even to have had a haircut. The camera angles weren't conclusive, but it's safe to assume at least half were sporting coat-tails. Everyone did well; including energetic John and lazy Susan. Winston - chuckling, cranky, avuncular - outperformed Colin Craig. Metiria Turei, at ease but still impassioned, was the other standout. The mutual fondness between Peters and Turei was clear. Who knows, maybe the Greens and NZ First could work together after all.
Fran O'Sullivan, columnist
Winner: Colin Craig
Colin Craig will have John Key weighing up whether to have that chat about East Coast Bays. Craig put the ball in John Key's court by predicting the PM would win and the Conservatives could help. There was a clear cleft between the parties who want to tax more and those who want to tax less. His opponents rolled their eyes at Craig's apparent political naivety. But by dialling back the moralistic overtones, Craig positioned the Conservatives as a possible partner to National. Smart work Colin.
