The two-day meeting at Panmunjom, on the heavily fortified inter-Korean border, came after the North agreed to disable by December 31 its plants producing material for atomic weapons.

"We are gathered here to conduct the quite difficult business of providing energy and economic assistance," South Korea's chief negotiator Lim Sung-Nam said in a speech carried by Yonhap news agency.

He said the energy-starved country had already provided a list of energy equipment and assistance it wants to receive in return for its nuclear shutdown.

The road ahead could be bumpy "primarily because we'll be discussing extremely technical issues," he said.

The North conducted a nuclear weapons test in October 2006 before agreeing to declare and disable its nuclear programmes in return for one million tons of heavy fuel or equivalent energy aid.

South Korean officials have said it wishes to receive aid equivalent to about 500,000 tons of oil rather than the fuel itself -- partly in the form of assistance to patch up its decrepit power plants.

The North has so far received 50,000 tons of oil each from South Korea and China. South Korean oil refiner GS Caltex said a ship carrying 21,000 tons of heavy oil provided by the United States -- the first shipment of a 50,000-ton consignment -- would arrive in the North later Monday.

Hubert Pirker, an Austrian member of the European Parliament, said Monday that he sees a sense of urgency in North Korea to meet its commitments made at the six-party talks.

The discussions group the two Koreas, the United States, Russia, China and Japan.

"I think they understand that only the success of six-party talks can bring better economic development for the North, better cooperation between North and South Korea and bring back North Korea to the international community," Pirker told Yonhap after a visit by EU parliamentarians to Pyongyang.

The North shut down its main nuclear reactor at Yongbyon and four other related facilities in July, and allowed inspectors from the UN atomic watchdog back into the country.

The disablement, to be supervised by US experts, aims to ensure the plants cannot quickly be brought back on line.

If the North goes on next year to dismantle the plants, and hand over its plutonium stockpile and any nuclear weapons, it can expect normalised relations with the United States and Japan, a lifting of sanctions and a pact formally ending the 1950-53 Korean War.