US President Donald Trump will urge all countries to join forces to isolate "the brutal regime of North Korea" on Wednesday, saying the world cannot tolerate "the menace of a rogue regime" that threatens it with nuclear devastation.

"Today, I hope I speak not only for our countries, but for all civilised nations, when I say to the North: Do not underestimate us. And do not try us," according to excerpts of a speech Trump is set to deliver to South Korea's parliament.

"We will not allow American cities to be threatened with destruction. We will not be intimidated," according to the excerpts.

"All responsible nations must join forces to isolate the brutal regime of North Korea - to deny it any form of support, supply, or acceptance."

- Reuters