China is resisting US-led efforts to order new sanctions against North Korea over its rocket launch and the UN Security Council could take weeks to decide a formal move, diplomats said.

Gary Locke, US ambassador to Beijing, said Monday that China and the United States are deeply divided over the best way to tackle North Korea's flouting of Security Council resolutions on using ballistic technology.

The 15-member Security Council, including China, condemned the rocket launch within hours after it took place Wednesday. Beijing has since signaled, however, that it will not add new sanctions to measures ordered after the North staged nuclear weapon tests in 2006 and 2009.

"There has been no serious discussion of any kind of resolution on North Korea," said one council diplomat. "With China in their current moo,d it will take weeks to get anything done and there is no guarantee that they will agree new measures," added a second envoy. Both spoke on condition of anonymity.

US Ambassador to the United Nations Susan Rice demanded last week that the Security Council make it clear that North Korea will face "consequences" for its actions.

Rice and China's UN envoy Li Baodong clashed during closed Security Council negotiations on a statement released Wednesday, diplomats said.

The following day, China's foreign ministry said any Security Council response had to be "prudent, appropriate and conducive to peace and stability on the Korean peninsula and avoid the escalation of the situation."

As one of the five permanent members of the council, China could block any resolution needed to order new sanctions.

But diplomats said new firms and entities could be added to the current sanctions list without a resolution. The UN Security Council has also yet to put any North Korean individuals on its sanctions list.

"There are ways to increase pressure, but clearly it would be better for the council to be united with China behind any action taken," said the council diplomat.

Locke told the Asia Society in New York that the United States is "really engaging diplomatically with China and other members of the United Nations Security Council on tougher resolutions, possibly sanctions against North Korea."

"The Chinese believe that we need to give North Korea a chance, that we need to help them develop economically," said Locke, who has been US ambassador in Beijing for 16 months.

China wants to restart six-country talks on North Korea's nuclear weapons "and see if we cannot encourage better behavior from North Korea, as opposed to imposing sanctions now and trying to coerce North Korea into the fold and abiding by their international obligations."

Locke called it "a difference of opinion of strategy" between the United States and China.

China, United States, North Korea, Russia, South Korea and Japan last held formal nuclear weapons talks in 2007. The North withdrew from the talks in 2009 following Security Council condemnation of a rocket launch it staged.

"China really believes that we ought to re-engage with North Korea. The United States feels that every time we have tried to re-engage with North Korea, they basically turn around and fail to respond to their promises," Locke said. "And it gets us nowhere.

"So we don't believe that we should rewarding their bad behavior by sitting down and talking with them."

Locke and other observers say China is trying to press North Korea to copy its own economic transformation of the past 40 years.

Beijing has helped the North set up free trade zones and encouraged other countries to invest in the isolated state in the hope "that might lessen the isolation of North Korea and therefore hope that might influence their foreign policy and similarly their military policies," the US ambassador said.