The Prime Minister says the future of the TPP could hang on the outcome of the US presidential election.

John Key says the deal has "no chance" if Donald Trump wins. But if Hillary Clinton wins, Mr Key believes there's a "a possibility and a window" for success.

He concedes the Democratic candidate has gone a little cool on the idea, but believes that's because she doesn't think the TPP is as good a deal, as she first thought.

"And so that would argue that she would want to come back to the table," Key said at his post cabinet press conference.

Key is also skeptical that Republican candidate Donald Trump would be able to implement his trade policy, which includes imposing a 45 per cent tariff on imports from China and threats to take the United States out of the World Trade Organisation.

"First he's got to win the election, second he's got to implement the policy and probably may well need Congressional support for that, so there's quite a lot of distance to travel."

The Trans Pacific Partnership trade deal among 12 countries, signed in New Zealand in February, could pass in the lame duck period.

Republican Speaker Paul Ryan said in August that the numbers weren't there although "Inside US Trade" reports that the Obama Administration is close to a solution on the biologics part of the TPP deal that has upset Republicans.

The lame-duck period is the session which meets after its successors have been elected but before they have been sworn in.

Congress is expected to resume in the week of November 14 for a month-long session, before a new President and Congress take over later in January.

In terms of TPP passing Key said: "It's definitely possible."

"I think it's a bit 50-50 myself."

Key said any kind of "anti-globalisation commentary" was negative for New Zealand.

"We are a small country positioned at the bottom of the world. We have a tiny population and our big opportunities lie when New Zealand companies get those opportunities to access middle-income consumers around the world including in the US."

In terms of the United States presence in the Asia Pacific, Key said it would be difficult to believe the US would have a reduced presence even with a Trump win.

Additional reporting by Audrey Young of the New Zealand Herald