North Korea's foreign minister has brushed aside US President Donald Trump's threat to destroy his country, comparing it to a "dog's bark".

Trump used his maiden address at the UN General Assembly on Tuesday to warn Pyongyang that Washington would "totally destroy" it if the US or its allies were attacked.

Arriving in New York for the UN meetings on Wednesday, Ri Yong-ho, the North Korean foreign minister, was mobbed with questions from reporters about the Trump speech and he replied with a proverb.

"There is a saying that marching goes on even when dogs bark," he said as he entered his hotel.

"If they are trying to shock us with the sound of a dog's bark they are clearly having a dog dream."

READ MORE: US - North Korea to be 'destroyed' if behaviour continues

North Korea says it needs a strong nuclear deterrent to protect it from an aggressive US, and the autocratic regime has made militarism a central part of its national ideology.

The country's stated aim is to be able to target the US mainland, and the nation has flaunted the advances in its weapons programme in recent weeks, with the September test of what it said was a miniaturised hydrogen bomb capable of being loaded onto a rocket.

The provocations have frayed the patience of the US and its allies.

Trump dubbed the North's leader Kim Jong-un, "Rocket Man", and said he was on a "suicide mission".

When asked by reporters what he thought of Trump calling Kim "Rocket Man", Ri quipped: "I feel sorry for his aides."

Ri is due to make a UN speech on Friday.

Shinzo Abe, Japan's prime minister, told the UN that dialogue with North Korea would not work.

The comments are likely to dismay China - North Korea's only major ally and trading partner - which has consistently called for a resumption of talks.

Observers say despite the tough rhetoric, any military response to the crisis would risk a devastating conflict that would imperil millions.

North Korea has fortified its southern frontier with a hefty arsenal of artillery that has South Korea's capital, Seoul, just 55km away, in its sights. Japan is also within range of missile attacks.