Major US allies in Asia today welcomed the UN Security Council's unanimous vote to step up sanctions on North Korea, with its profitable textile exports now banned and fuel supplies to the reclusive North capped after it its sixth nuclear test.

Japan and South Korea said after the passage of the US-drafted Security Council resolution they were prepared to apply more pressure if Pyongyang refused to end its aggressive development of nuclear weapons and ballistic missiles.

Monday's decision was the ninth sanctions resolution unanimously adopted by the 15-member Security Council since 2006 over North Korea's ballistic missile and nuclear programmes.

A tougher initial US draft was weakened to win the support of China, Pyongyang's main ally and trading partner, and Russia, both of which hold veto power in the council.

"We don't take pleasure in further strengthening sanctions today. We are not looking for war," US Ambassador to the United Nations Nikki Haley told the council after the vote. "The North Korean regime has not yet passed the point of no return."

"If it agrees to stop its nuclear programme, it can reclaim its future ... if North Korea continues its dangerous path, we will continue with further pressure," said Haley, who credited a "strong relationship" between US President Donald Trump and Chinese President Xi Jinping for the successful resolution negotiations.

Kim Jong Un meets supporters. Photo: North Korean central news agency

UN member states are now required to halt imports of textiles from North Korea, its second largest export after coal and other minerals in 2016 that totalled $752 million and accounted for a quarter of its income from trade, according to South Korean data. Nearly 80 percent went to China.

"This resolution also puts an end to the regime making money from the 93,000 North Korean citizens it sends overseas to work and heavily taxes," Haley said.

"This ban will eventually starve the regime of an additional $500 million or more in annual revenues," she said.

Resume dialogue

South Korea's presidential Blue House said on Tuesday the only way for Pyongyang to end diplomatic isolation and become free of economic pressure was to end it nuclear programme and resume dialogue.

"North Korea needs to realise that a reckless challenge against international peace will only bring about even stronger international sanctions against it," the Blue House said.

However, China's official Xinhua news agency said in a commentary that the Trump administration was making a mistake by rejecting diplomatic engagement with the North.

"The US needs to switch from isolation to communication in order to end an 'endless loop' on the Korean peninsula where "nuclear and missile tests trigger tougher sanctions and tougher sanctions invite further tests," Xinhua said.

Japanese Prime Minister Shinzo Abe quickly welcomed the resolution and said after the vote it was important to change North Korea's policy by imposing a higher level of pressure.

The UN Security Council votes on sanctions. Photo: Reuters

'US gangsters'

The resolution imposes a ban on condensates and natural gas liquids, a cap of 2 million barrels a year on refined petroleum products, and a cap on crude oil exports to North Korea at current levels. China supplies most of North Korea's crude.

A US official, familiar with the council negotiations and speaking on condition of anonymity, said North Korea imported some 4.5 million barrels of refined petroleum products annually and 4 million barrels of crude oil.

Pyongyang warned the United States on Monday that it would pay a "due price" for spearheading efforts on UN sanctions over its nuclear programme, which it said was part of "legitimate self-defensive measures".

"The world will witness how (North Korea) tames the US gangsters by taking a series of actions tougher than they have ever envisaged," the foreign ministry said in a statement carried by the official KCNA news agency.

However, North Korea did not issue a response immediately after the adoption of the latest resolution.

Chinese officials have privately expressed fears that an oil embargo could risk causing massive instability in its neighbour. Russia and China have also expressed concern about the humanitarian impact of strengthening sanctions on North Korea.

Haley said the resolution aimed to hit "North Korea's ability to fuel and fund its weapons programme". Trump has vowed not to allow North Korea to develop a nuclear missile capable of hitting the mainland United States.

International will

South Korean officials said after the North's sixth nuclear test that Pyongyang could soon launch another intercontinental ballistic missile in defiance of international pressure. North Korea said its Sept. 3 test was of an advanced hydrogen bomb and was its most powerful by far.

The latest resolution contained new political language urging "further work to reduce tensions so as to advance the prospects for a comprehensive settlement".

China's UN ambassador, Liu Jieyi, called for a resumption of negotiations "sooner rather than later." He called on North Korea to "take seriously" the will of the international community to halt its nuclear and ballistic missile development.

The resolution also calls on states to inspect vessels on the high seas, with the consent of the flag state, if they have reasonable grounds to believe the ships are carrying prohibited cargo.

It also bans joint ventures with North Korean entities, except for non-profit public utility infrastructure projects.