Prime Minister John Key says Winston Peters' dislike of him stands in the way of a deal between National and NZ First in 2014.
Mr Key said he expected Mr Peters to back a Labour government, despite his long-standing clashes with the Green party.
"I think that the argument that he really really dislikes the Greens, let's put it politely, that's all true . . . but he's not overly enamoured with me," Mr Key said.
He and Mr Peters had chatted during a trip to Samoa as part of a New Zealand delegation.
"I had a brief chat to him but realistically I think he will go with Labour . . . Even if we were prepared to change, and that would be a big if, he was always going with Labour . . . in 2008," he said. "I think it's just personal."
Mr Key had ruled out working with Mr Peters but, since the last election, he has left the door open to a deal in 2014. He said any personal animosity was not mutual.
"I don't hate Winston at all. I think in a lot of respects I have respect for him as an MP. But he's an Opposition MP. That's where he loves it."
Mr Peters laughed at Mr Key's comments.
"Is he getting all sensitive now is he? Ha ha ha. Good Lord."
Mr Key ruled out a deal with him over the Owen Glenn donations furore in 2008, and said he did not meet his standards, "when he had no fact to fly on".
"You've got to be pretty, pretty arrogant to make a statement like that," Mr Peters said. "Anybody, even a fly parachuting out of the rear end of a snake, could do better than what Merrill Lynch have done over the last few years, and they have been doing it for years."
Before he came into politics, Mr Key was global head of foreign exchange at merchant bank Merrill Lynch.
Mr Peters said NZ First was pushing a brand of politics important for the country's recovery.
"If they don't like it, they don't like it but to start personalising it is stupid."
He recalled an "apolitical" chat with Mr Key on the trip to Samoa, but no "angst".
Mr Key said he had other options if NZ First did not back National.
However, his main support options polled weakly in today's Fairfax Media-Ipsos poll.
ACT failed to register; UnitedFuture recorded 0.2 per cent, leader Peter Dunne could retain his Ohariu seat; and the Maori Party, which could switch to Labour after the 2014 election, registered 1.3 per cent but may retain some or all of its three electorate seats.
- © Fairfax NZ News
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