Hopes had been raised by milestone talks between US and North Korean envoys in Berlin in January.
South Korea's envoy to the negotiations, Chun Yung-woo, said: "We have confirmed that there is a consensus among the countries that there must be an agreement on the early steps on implementing the September 19 joint statement at this round [of negotiations]."
He was referring to the North's agreement with the five other countries in September 2005, so far not implemented, to stop its nuclear weapons programme in return for economic and security concessions.
Christopher Hill, the US chief delegate, said the six parties were "coalescing around some of the themes" that would be part of an initial agreement, and also said China may start circulating something "either later tonight or tomorrow morning".
"We hope we can achieve some sort of joint statement," he said.
Earlier, Japan's chief delegate demanded that North Korea freeze a nuclear reactor as the first step towards nuclear disarmament, in line with expectations after the preliminary discussions, and said that any deal needed to be implemented fast.
"Regarding denuclearisation, North Korea needs to halt and seal its operations of the nuclear facilities in Yonbyong and accept verification and monitoring by the IAEA," Kenichiro Sasae told Thursday's meeting, according to a draft of his speech released by Japan's foreign ministry.
"The initial-stage steps must be implemented in a relatively short period of time."
Sasae later said North Korea had stated its own position on how to denuclearise the country, but he did not elaborate.
"As of today, there is no specific conclusion," he said.
Negotiators from the two Koreas, the US, Japan, Russia and China gathered in a secluded compound in western Beijing amid reports North Korea may be persuaded to suspend the facilities that helped it stage its first nuclear test last year.
"So far the denuclearisation of North Korea has been mostly talk versus talk. Now it's time to enter the stage of actions versus actions," Chun said earlier.
Kim Kye-kwan, the North Korean chief negotiator, told China's official Xinhua news agency before leaving Pyongyang he did not "expect too much" from the talks and their fate lay in US hands.
"We are prepared to discuss the initial steps, but the judgment [for the talks] should be based on whether the United States will come forward and abandon its hostile policy against us and co-exist peacefully," he said on arrival in Beijing.
Participants have dismissed hopes of an immediate settlement of the long-burning stand-off in this session of the stop-start talks, first convened in the Chinese capital in August 2003.
Distrust between North Korea and others in the talks deepened after Pyongyang's nuclear test last October, which prompted UN sanctions backed even by China, the North's long-time supporter.