Simon Bridges says if he was at the United Nations event being held in New York, he would not of laughed at US President Donald Trump.

World leaders chuckled at Trump's boast to the UN General Assembly that in less than two years, his administration had achieved more than almost any other in US history.

Prime Minister Jacinda Ardern kept a straight face, and wouldn't be drawn on her views afterwards.

Bridges says although President Trump may be a polarising character, he deserves respect and this incident was unfortunate.

“There are some things which he is doing which I agree with, and as the President of the United States, he deserves our respect. I certainly would not be laughing.”