Just last month he was saying he thought there was a 50-50 chance of the deal going through.
But he's talking a different tune now after Government leaders were stunned last night over the election of Donald Trump as United States President over Hillary Clinton, a firm friend of New Zealand.
"We'll work our way through it, it's bad in the sense that it's very hard to see TPP progressing now in the lame duck period, you'd have to be a real optimist to believe that," he told Newstalk ZB's Mike Hosking.
The United States led the Trans Pacific Partnership, a legacy trade deal for outgoing President Barack Obama, but it was concluded among the 12 countries only a year ago, and it has not been ratified.
With $5.6 billion of exports to the US, it is New Zealand's third largest trading partner behind China and Australia.
But US Senate Majority Leader Mitch McConnell on Wednesday dashed any remaining hopes that the deal would come up for a vote before Mr Trump took office in January.
"It's certainly not going to be brought up this year."
Mr McConnell said any decisions on TPP or other future trade agreements would be up to Mr Trump, who would still have the authority for four more years to negotiate "better deals" with expedited approval procedures in Congress.
Trump excoriated TPP on the campaign trail as a "disaster" and "a rape of our country," tapping into populist anger at globalization, trade and manufacturing job losses that helped propel his candidacy.
John Key and Finance Minister Bill English said New Zealand needed to be confident it could adjust to the effects of a Trump administration.
"If there's a policy change in areas like trade, well we'll have to learn to live with that. New Zealand's a very attractive destination, we do things well, and whatever happens in the US we'll learn to work with it," he said.
"Whatever ultimately happens, New Zealand has got a good relationship with the United States."
Mr English described the result as "pretty stunning" and said New Zealand would feel the economic effects.
"Some of the waves will wash up here, whatever they are, and we can't predict them," he said on Newstalk ZB.
"But it is important we are resilient and confident about our ability to deal with this uncertainty.
"In the long run, the US has a vigorous capitalist economy full of people who want to get ahead and they're unlikely to go along with policies that will fundamentally hamstring them."
Asked if it would mean the TPP was down the gurgler, Mr English said "if you believe the rhetoric, that would be the case."
However, he said if the US wanted economic leadership in the Asia Pacific it knew it needed a trade agreement which included most of that region.
Former trade negotiator and lobbyist Charles Finny said a Donald Trump presidency was "not ideal" for trade ties with the United States.
"Things like the Trans Pacific Partnership [TPP] will become a lot more complex.
"But Trump had been talking quite positively about negotiating good deals, possibly new types of deals and bilateral deals.
"And I'm sure we'd be very keen to work with the administration on that too."
He still had some hope the TPP would get through during the Obama administration's "lame duck" period - between now and when the new Congress is sworn in in January.
If that was not possible, it was likely to be delayed for years, he said.
New Zealand would have to build "as constructive as possible a relationship" with the US, Finny said.
"It's a very key trading partner, a very key political partner, and we're going to have to work very closely with the new administration."
US ambassador to New Zealand Mark Gilbert, a good friend of Mr Obama, hosted an election event at a Wellington bar yesterday.
As he left the function he was asked what a Trump presidency would mean for trading countries like New Zealand.
"I'll answer that as if I am the world markets," he said.
"They have traded off dramatically since he took the lead. So the world markets have already expressed their voice. As a diplomat, I can't express mine."
But he added that the US relationship with New Zealand "will still be strong."
- New Zealand Herald and Reuters
