Chief envoys from six nations negotiating the end of North Korea's nuclear programme held talks in Beijing on Thursday after a nine-month break, host nation China said.

The meeting would focus on 'steps and measures' to achieve the 'comprehensive and balanced' implementation of an agreement between the six nations, foreign ministry spokesman Qin Gang said.

The chief negotiators from North Korea, the United States, China, South Korea, Japan and Russia could continue their talks for up to three days, depending on progress, Qin said earlier.

The appraisal of a long-awaited nuclear declaration delivered by Pyongyang in late June and the establishment of a verification mechanism will be on the agenda at the talks, Kim Sook, South Korea's chief nuclear envoy, told Yonhap news agency.

The day after handing over the declaration to China, North Korea destroyed a cooling tower at its Yongbyon plant in a move to show it would dismantle its controversial programme.

In exchange for the declaration, Washington plans to take the communist country off its list of countries accused of supporting terrorism, and to lift economic sanctions against Pyongyang.

Last week, North Korea's foreign ministry said it would only take further steps towards disarmament if the agreed on energy and economic aid to the country can be accelerated.

Yonhap quoted Kim Sook as saying on Thursday that Japan's participation in energy aid to North Korea was essential to concluding the second phase of the denuclearization process.

'I will urge Japan to participate in the economic and energy aid in which North Korea is interested,' Kim said.

'Concrete plans for it can be fleshed out at a related working group,' he was quoted as saying.

Qin said two working groups on denuclearization and compensatory energy aid to North Korea would also meet in Beijing this week.