US PRESIDENT Donald Trump has vowed slap new “major sanctions” on North Korea after it fired off its most powerful missile yet — but experts say further punishments will only make the rogue nation work harder on its weapons program.

Mr Trump spoke to Chinese President Xi Jinping overnight, and tweeted that the fresh sanctions would be imposed today in response to the North’s “provocative actions”.

“This situation will be handled!” Mr Trump tweeted.

On the call, Mr Trump stressed the determination of the US to defend itself and its allies from the “growing threat posed by the North Korean regime”.

“President Trump emphasised the need for China to use all available levers to convince North Korea to end its provocations and return to the path of denuclearisation,” the White House said in a statement.

North Korea test-fired a Hwasong-15 intercontinental ballistic missile into Japanese waters early Wednesday morning.

While the Trump administration is focused on sanctions to stop Mr Kim’s weapons program, experts have questioned whether the strategy is working.

Leading North Korea journalist, CNN’s Will Ripley, tweeted that the tactic had actually motivated the hermit kingdom to “work harder developing nukes”.

Unprecedented sanctions have done little to slow North Korea’s nuclear advance thus far. But it seems that’ll continue to be the Trump administration’s approach. North Korean officials have stated to me repeatedly sanctions only motivate them to work harder developing nukes. https://t.co/nRm4h9QGCW — Will Ripley (@willripleyCNN) November 29, 2017

International security expert John Blaxland told news.com.au yesterday that the latest launch showed the tough sanctions were not having the desired effect.

“It strongly suggests sanctions are not working, that Kim plans to continue to defy the collective international pressure and that, if pressed further, could result in an attack in a manner reminiscent of Japan’s attack following the US-imposed oil embargo that preceded the attack in Pearl Harbor in December 1941,” said Prof Blaxland, who is the director of the Australian National University Southeast Asia Institute.

“Like a cornered rat, KJU is displaying the tendencies of one prepared to strike out violently.”

Australia’s Foreign Minister, Julie Bishop, has said repeatedly that the United Nations-backed sanctions regime is the best way to stop North Korea’s military build-up and “change its behaviour”, but that it needs time for its effects to be felt.

Yesterday’s launch showed how far North Korea’s missile technology has advanced, with the missile reaching an altitude of 4475km, which is 10 times higher than the orbit of the International Space Station.

North Korea crowed in a special TV broadcast that the test showed it was now “capable of striking the whole mainland of the US” with a “super-large heavy warhead”.

Experts agreed that the US’s east — including the power centres of Washington DC and New York City — were within striking range. US defence secretary Jim Mattis said North Korea was aiming to build the ability to hit “everywhere in the world basically”.

According to North Korean state media, leader Kim Jong-un “declared with pride that now we have finally realised the great historic cause of completing the state nuclear force, the cause of building a rocket power”.