North Korea has "no thoughts" of resuming six-party talks on its nuclear programme, a top official said in Beijing, despite the repeated urgings of its closest ally China.

The North quit the now-stalled negotiations aimed at curbing its nuclear weapons programme in 2009, and soon afterwards carried out its second atomic test.

The talks are hosted by China, and include South Korea, the United States, Russia, and Japan.

China, North Korea's main diplomatic protector and economic benefactor, wants to revive negotiations, although the US, South Korea and Japan all insist North Korea, which carried out two missile launches earlier this week, must first take some tangible steps towards denuclearisation.

Choe Son-Hui, deputy director-general of the North American affairs bureau in North Korea’s foreign ministry, said in Beijing: "For now, we have no thoughts about taking part in talks to discuss the DPRK's denuclearisation."

She was in the Chinese capital for an annual security forum, which includes representatives from each of the six parties.

"Under these circumstances where the US hostile policy is still there, DPRK is not in a position to talk about denuclearisation of the Korean peninsula," she told reporters in English outside the country's embassy, using its official name.

Ties between China and the North have become strained in recent years as the government in Pyongyang has pressed ahead with internationally-condemned nuclear tests, and with Kim Jong-Un yet to visit Beijing three years after inheriting power.

After a string of failures in recent months, North Korea successfully tested two powerful Musudan medium-range missiles yesterday, one of which flew 400km into the Sea of Japan.

Existing United Nations measures prohibit North Korea from using ballistic missile technology.

After North Korea conducted a fourth nuclear test on 6 January, followed by a long-range rocket launch on 7 February, the UN Security Council adopted its most punishing sanctions yet against North Korea.

Any further measures would require the support of veto-wielding permanent council member China, which has shied away from additional action in favour of calls for resuming the six-party talks.

"We are not at all disappointed by the Chinese," Ms Choe said, denying that North Korea felt a lack of support from its neighbour.

"China is doing what she has to do, and we are doing what we have to do."