The UN Security Council will ban the export of racing cars to North Korea on Thursday and launch an international hunt for its diplomats carrying suitcases of cash.

But no-one expects Pyongyang to halt its campaign of nuclear provocation.

Following an agreement between the United States and China, the 15-member council will put North Korea under one of the toughest sanctions regimes ever ordered as a punishment for its February 12 nuclear bomb test.

But the hot-tempered North Korean government gave its response before details of the proposed sanctions were even released -- threatening to pull out of the armistice that halted the 1950 to 1953 Korean War.

Despite the sanctions, the world must brace for "a lot more saber rattling," said Philip Yun, a veteran North Korea watcher and executive director of the Ploughshares Fund, a US-based foundation pushing for an end to nuclear weapons.

The sanctions seek "pressure points" to further isolate North Korea, cut off the supply of luxuries to its leaders and hinder efforts to secure money and technology for nuclear bombs and long-range rockets, according to diplomats.

The sanctions resolution specifically names jewelry, yachts, racing cars and other high class automobiles as luxury items that must not be sent to North Korea, said one UN diplomat.

Luxury items were banned after the North's first nuclear test in 2006. But member states were left to make their own decision what constituted "luxury."

An Austrian businessman was caught in 2009 trying to send multi-million dollar yachts to the North and S-class Mercedes are regularly seen on the streets of Pyongyang.

A diplomat said the measures "would get at the ruling elite who are living these rather lavish lifestyles while the rest of the country is impoverished."

The resolution adds three new individuals and two new firms to the list subject to a travel ban and assets freeze. It would also ban trade components that could be used for uranium-enrichment, the UN envoy said.

But special attention will now be paid to North Korean diplomats around the world as the resolution targets what the envoy called "whole new areas and target entire new types of illicit behaviour by North Korea."

UN members will now be under a "binding obligation" to halt "any financial transaction or any financial service that could contribute to North Korea's illicit" nuclear and missile programs and weapons sales.

The United States believes North Korea gets huge amounts of money from abroad through "bulk cash transfers".

"They are already subject to sanctions so they literally move money in suitcases full of cash," said the UN envoy.

The resolution calls on UN states to "exercise vigilance" about North Korea's diplomats.

"We know there have been diplomats out there cooking up deals, moving funds around and engaging in activities they shouldn't," said the UN envoy.

The resolution "will take the UN sanctions imposed on North Korea to the next level, breaking new ground and imposing significant new legal obligations," said US ambassador Susan Rice, who negotiated with China.

"This is likely to make North Korea very mad, but the council had to act and it does have China on board," said another senior UN diplomat.

Yun, at the Ploughshares Fund, said "it is going to be extremely difficult to prevent North Korea from doing what it wants to do."

He said it was no accident that Kim Jong-Un, still a newcomer to leadership, had allowed the nuclear blast with new governments in South Korea and Japan and President Barack Obama just starting a second term.

The North moved "to basically keep everybody off balance before anyone can get into place. This is kind of a test in itself of the governments' response."

The United States had to seek "robust" sanctions and China had no choice but to agree as it is a permanent Security Council member, said Yun.

But to have any impact on North Korea, the United States and China, which has traditionally shielded its ally, must agree a plan of action with South Korea and Japan, he said.