South Korea's delegation, led by Deputy Foreign Minister Song Min-soon, flew to Beijing on Thursday on a previously scheduled two-day visit. He met Chinese Vice Foreign Minister Wu Dawei.
"We can't expect to resolve this in a short period of time. We should take a long-term perspective, and we will resolve it in a calm manner," Song told reporters upon arrival in Beijing.
The recently named top US nuclear negotiator for the Beijing talks, ambassador to South Korea Christopher Hill, also flew to Beijing for one day of meetings with Chinese officials.
He was upbeat on returning back to South Korea, saying he exchanged views with the Chinese on what each of the countries could do to have successful negotiations, Yonhap news agency reported.
Chinese Foreign Ministry spokesman Kong Quan said earlier Hill would meet Wu as well as Foreign Minister Li Zhaoxing. He said Ning Fukui, China's special envoy for Korean nuclear issues, was also likely to attend the meetings.
The diplomatic flurry precedes a trip to North Korea on February 19 by senior Chinese Communist party official Wang Jiarui - an apparent attempt to salvage the talks, which also include long-time North Korean ally Russia and neighbouring Japan.
China is North Korea's main benefactor and US officials, while grateful to Beijing for having coaxed the reclusive country to the negotiating table three times, have increasingly faulted the Chinese privately for failing to exert even more influence.
Kong said China remained committed to the six-party process and pressuring North Korea was not the answer.
"We believe this kind of tactic will not create a resolution but instead raise tensions," he told a regular news briefing.
"Complication of the issue will complicate the safety and security of the region."
The six countries have met three times in Beijing. A fourth round of talks planned for September 2004 never materialised, with Pyongyang saying Washington must first drop its hostile policy towards the North.
South Korea's ambassador to China, Kim Ha-joong, said Beijing's influence on the North was far greater than believed.