The UN Security Council may have sharpened the teeth of its sanctions regime on North Korea, but analysts doubt it has the bite to put an increasingly belligerent Pyongyang off its nuclear programme.

Thursday's adoption of a sanctions resolution by the 15-member council was almost drowned out by the North's vitriolic rhetoric, which threatened nuclear strikes against the US and the scrapping of peace pacts with South Korea.

The resolution, drafted in response to North Korea's third nuclear test last month, sought to disrupt Pyongyang's financial lifelines by targeting banking, trade and shipping activities.

It made some existing measures mandatory and put a spotlight on North Korean diplomats long suspected of ferrying around suitcases packed with cash to circumvent economic sanctions.

Although US ambassador Susan Rice predicted the new measures would "bite hard", analysts said it would largely depend on who was doing the biting.

"Beijing is the key actor with regard to all the banking and trans-shipping issues," said Marcus Noland, a North Korea expert at the Peterson Institute for International Economics in Washington.

It is in China that military-connected North Korean entities have established banks or other institutions to intermediate the financial flows associated with its nuclear development and proliferation programme.

"If the Chinese choose to enforce the resolution rigorously, it could seriously disrupt if not end North Korea's proliferation activities. Unfortunately, if past behaviour is any guide, this is unlikely to happen," Noland said.

China, which is North Korea's sole major ally, has often been criticised for displaying a less-than-enthusiastic commitment to implementing existing sanctions and shielding Pyongyang from harsh new ones.

While few doubt Beijing's opposition to the North's nuclear tests, China's priority is seen as staving off any regime collapse that might result in a reunified Korea under the control of a US-allied South.

Much has been made of the fact that China was involved in drafting the latest UN resolution, thus lending it more weight and credibility.

But analysts like Victor Cha, who holds the Korea Chair at the Center for Strategic and International Studies, were underwhelmed.

"We have been socialised into expecting so little from China that there's excitement when China shows even a bit of sternness," Cha said.

"The real test of China's commitment will be in the follow-through. Will it not just sign on to sanctions, but will it enforce them with vigour?

"In the past, China-North Korea trade has increased in the aftermath of UN sanctions," he added.

Some hawkish observers had hoped the Security Council resolution might invoke Chapter 7 of the UN Charter, which allows for the use of military force in enforcing sanctions.

As it stands, Noland noted that the provisions contained what amounted to a "credible information" clause that could provide a loophole for UN members wary of cracking down on illicit North Korean activities.

"A government which does not want to enforce them can say that they lack credible information, or that the information that they were provided did not meet the standard of 'reasonable grounds'," Noland said.

"Given the modesty of this package and North Korea's apparent determination to build its nuclear and missile programmes, (the resolution) is unlikely to have a great effect," he said.

In terms of resolving the North Korean proliferation challenge, "sanctions alone can only buy time", he added.

North Korea's furious response to the resolution and its threats of nuclear Armageddon have largely been dismissed as bluster, but their shock value plays into the hands of those stressing the need to calm tensions and engage Pyongyang.

Paik Hak-Soon, a North Korean analyst at the Sejong Institute in Seoul, predicted that Pyongyang would do whatever it took to keep the alarm bells of the international community ringing.

"It's cornered more than ever in the international community and will keep pushing ahead with even more confrontational moves militarily," Paik told AFP.

"Sanctions haven't worked before and they won't work now. The real problem is there is absolutely no creativity in the way countries like China, the US and South Korea deal with the North," he said.