"China has always stood firmly in maintaining peace and stability on the Korean peninsula and will actively propel parties concerned to solve the nuclear issue through peaceful dialogue," said Vice President Zeng Qinghong.
"China holds that the Korean peninsula should be nuclear-free and reasonable security concerns of the Democratic People's Republic of Korea (North Korea) should be addressed," he said.
China, which has been instrumental in coordinating the latest round of discussions, has called them a "significant opportunity" for solving the crisis, although few observers expect concrete results.
Together with Russia - the other nation with the closest access to leaders of the hermetic Stalinist state - China has offered to issue an official security guarantee to North Korea, which the United States refuses to do in a formal treaty.
Russian Deputy Foreign Minister Alexander Losyukov on arrival in Beijing said he was "discreetly optimistic" about the talks.
Diplomats attending the talks broke off into bilateral and trilateral unofficial meetings on Tuesday ahead of the official three-day talks starting Wednesday to fine-tune their positions.
"We are going to compare notes and hold discussions with each other and then we are going to decide what we are going to talk about tomorrow," said a Japanese embassy spokesman said.
Chief delegates from all nations except North Korea were scheduled to meet in different venues to coordinate their approaches.
China was to hold bilateral talks with Japan and South Korea at the Chinese foreign ministry, officials from Japan and South Korea said.
"China holds that the Korean peninsula should be nuclear-free and reasonable security concerns of the Democratic People's Republic of Korea (North Korea) should be addressed"
Chinese Vice President
One-on-one talks between Russia and Japan and Russia and South Korea were also scheduled.
US envoy James Kelly meanwhile sat down with his counterparts from Japan and South Korea in a trilateral setting at the South Korean embassy, a US embassy spokeswoman said.
The flurry of meetings are to be followed by an informal reception in the evening, hosted by China, for all six nations.
North Korea's 10-man delegation, headed by Kim Yong-Il, headed straight for the North Korean embassy compound on its arrival from Pyongyang Tuesday.
Yong-Il, 58, smiled at journalists but refused to answer questions as he was whisked away in a limousine.