Top US, Chinese and South Korean diplomats met Wednesday to renew efforts to nudge North Korea back to stalled nuclear disarmament talks, but there were no signs of any progress.

China, host of the six-party talks and the communist North's only major ally, has said the future of the on-off talks depended on the willingness of Washington and Pyongyang to work together.

The talks began in 2003 and have been on hold since the North stormed out 10 months ago.

Upon arriving in Beijing Wednesday, Washington's special North Korea envoy Stephen Bosworth met with his Chinese counterpart Wu Dawei to assess the prospects of resuming negotiations, but reported little progress.

"We just completed a very useful exchange of views ... on the status of efforts to resume the six-party process," Bosworth told reporters following his meeting.

"Everybody shares the view that it is important to get back to the negotiating table as soon as we can, (but) I wouldn't try to characterise one way or another the current state of play."

South Korean chief negotiator Wi Sung-Lac also met Wu as part of a two-day visit to Beijing that began on Tuesday.

South Korea's Yonhap news agency quoted Wi saying his talk with Wu was "constructive" but that the future remained unclear.

"We will have to wait and see because it is still not clear how the consultations (on the resumption of the six-party talks) will go," he added.

The Chinese envoy briefed Wi about North Korea's preconditions for a return to the six-nation forum as outlined by its chief nuclear negotiator Kim Kye-Gwan during a visit to Beijing two weeks ago.

Media reports have said the North is insisting on two conditions for returning to dialogue: the lifting of UN sanctions and a US commitment to discuss a formal peace treaty on the Korean peninsula.

The United States, South Korea and Japan say the North must first return to dialogue and show it is serious about denuclearisation.

An unnamed South Korean official who attended the meeting between Wi and Wu added: "We could not see any significant changes (to North Korea's demands), but it was very useful to review current conditions with China."

Bosworth, who was travelling with US chief nuclear negotiator Sung Kim, was due to visit Seoul -- where he will meet Wi -- and Tokyo after his stop in Beijing. Russia is also a member of the six-party forum.

Under deals in 2005 and 2007 the North agreed to scrap its nuclear weapons in return for aid and major diplomatic and security benefits, including a formal peace pact.

But the talks became bogged down by disputes over ways to verify disarmament and in April last year the North quit them altogether.

On Tuesday, a senior North Korean Communist Party official, Kim Yong-Il, met his Chinese counterpart Wang Jiarui and President Hu Jintao.

The North Korean official discussed the nuclear issue and delivered a message from leader Kim Jong-Il to Hu, the China Daily reported.

Pyongyang, which tested atomic weapons in October 2006 and May 2009, says it developed nuclear weaponry because of a US threat of aggression, and it must have a peace pact before it considers giving them up.

The 1950-1953 Korean War ended only in an armistice. Seoul officials suspect talk of a peace treaty is an excuse to delay action on the nuclear programme.

South Korea's unification minister urged North Korea Wednesday to hold "sincere" talks with the South to remove the threat of nuclear arms from the peninsula.

The North says nuclear issues should be discussed mainly with the United States since it developed its atomic arsenal to counter US threats.

But minister Hyun In-Taek, in charge of cross-border relations, told a parliamentary forum the two Koreas could not fundamentally improve ties unless the North agrees to "heart-to-heart talks" on the nuclear issue with the South.