Two days after Donald Trump's incredible victory in the United States, Prime Minister John Key admits the idea of 'President Trump' is still "kind of weird".

"But he won, she lost, eat that... I think that is how they say it," Key told the Radio Sport breakfast show today.

Key said the modern world was "getting a bit more tricky", pointing to the Brexit and previous UK election result.

He said Trump's victory, in the face of polls which suggested Hillary Clinton would win, could perhaps be explained by several factors: the margin of error, the US state-by-state electoral system and the ways in which polls were conducted.


"Young people don't use the landline, it's much more difficult through email to get a proper sample, it (also) depends who turns out...there are a number of different factors. You have to take (polls with) a healthy grain of salt."

Another theory, said Key, was that people were more willing to vote for Trump in computer-generated polls, rather than telling a human pollster.

Key said some New Zealand politicians, or potential politicians, might see Trump's tactics and success and try to adapt accordingly.

"We might see a little bit of change at the next election (in New Zealand) where people try to amp it up both ways....sort of along the lines where Winston Peters goes, making pretty big promises and then, to be blunt, not being able to carry them out."

Key said Trump was a businessman and pragmatist and might make adjustments to the likes of the TPP deal in the next two to three years and come back to say, "hey it's (now) a great deal".