"It's fundamentally not right," says Key who loves America, has a holiday home in Hawaii, counts New York as one of his favourite cities in the world and Barack Obama as a friend.
"Instead of celebrating that they are... an amazingly successful country, they actually think they are losing.
"I know the slogan is to 'Make America Great Again' because he thinks it is hopeless."
Key says the election has been so divisive and "rugged" that it could take a very long time for America to come together.
"You've got a very divided American. You've had a lot of rhetoric which is quite ugly and in lot of ways a lot of self-doubt creeping into America about whether they are doing okay.
"And I just think it is has been quite a negative process and not actually a very satisfying process for the Americans."
Key says the question of who will win hasn't occupied too much of his thinking.
"At the end of the day we will work with whoever the president is and hopefully the relationship will continue to go from strength to strength."
Both candidates have criticized the Trans Pacific Partnership free trade agreement, although Trump has been more vehemently opposed than Clinton.
"I don't get a vote and I have to work with whoever the next president is," he said today.
"Obviously we'd like to advance some things that our Government passionately believes in," he said.
That included trade, economic liberalisation and globalisation.