BEIJING lacks leverage over North Korea (NK) and will block moves for strong new sanctions for fear of weakening its position further, Chinese state media said on Thursday following Pyongyang's rocket launch.

China is the North's sole major ally, considered the nation with the most influence over Pyongyang, and after Wednesday's rocket flight US officials urged it to intervene.

But in an editorial on Thursday the state-run Global Times said: "China's ability to influence countries in the region is limited . . . The real problem is China's strength is not sufficient to influence its neighbor’s situation."

"NK move shows China's lack of leverage" read its headline.

China voiced "regret" over the launch but state press said it could not support strong further measures against Pyongyang for fear of weakening its relationship.

A bellicose Western reaction risked driving North Korea into a corner with potentially devastating results, editorials said.

"That is why China should not take a cooperative stance with the US, Japan and South Korea in imposing sanctions on North Korea," the Global Times said.

"China will veto radical resolutions made by the three countries. At the same time North Korea should pay for its actions."

It acknowledged fears in the region should North Korea eventually be able to arm a ballistic missile with a nuclear weapon.

The reaction to the launch "is almost the same as that of North Korea's nuclear test", the paper said, and "a vicious circle" of escalation could lead to Japan abandoning its pacifist constitution and threaten peace in Northeast Asia.

The situation was "subtle, complex and dangerous", said the People's Daily, the official mouthpiece of the Communist Party, urging calm and a return to the six-party talks on North Korea hosted by China and including Russia, the United States, South Korea and Japan.

"The reaction by the Security Council should be prudent and measured," the paper added.

One columnist in Global Times, which often takes a nationalist stance, suggested that China should seize the opportunity to establish a regional security framework.

The country is embroiled in territorial disputes with Japan over islands in the East China Sea, and several littoral states over the West Philippine Sea (South China Sea), which Beijing claims almost in its entirety.

"Now it's high time to establish a political and security mechanism," wrote Ding Gang. "China is a big power in the region.

"China itself will certainly be confined by the mechanism, but the credibility it acquires will be more important. "The mechanism will not only regulate North Korea, but also the Philippines and Vietnam."