Donald Trump Vows To 'Totally Destroy' North Korea During Tough UN Speech

US President Donald Trump has addressed the United Nations General Assembly for the first time, making his strongest threat against North Korea to date.

Escalating his stand-off with the country over its ongoing nuclear testing, Trump threatened to "totally destroy" North Korea, while continually mocking leader Kim Jong-Un, calling him "rocket man".

"The United States has great strength and patience. But if it is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea," he said during his fiery speech.

"Rocket man is on a suicide mission for himself and for his regime. The United States is ready, willing and able, but hopefully this will not be necessary."

Australia's Foreign Minister Julie Bishop was in the audience and said the focus should "be on North Korea's behaviour, rather than the way the president may described it".

"The last thing anybody wants is for there to be conflict on the Korean Peninsula. The president made it quite clear that the consequences of that would be catastrophic," Bishop said.