"For the shutdown, disabling, and eventual dismantlement, the light-water nuclear reactor should come in," Kim Kye-Gwan told reporters at Beijing airport before leaving for Pyongyang.

Kim's comments follow nuclear disarmament talks in Beijing that ended Friday with the Stalinist state reiterating its intention to declare all its nuclear programmes and disable them in return for fuel aid and diplomatic concessions.

No deadline was agreed upon during the three days of talks that involve China, the two Koreas, the United States, Japan and Russia.

The talks began in 2003 to rein in North Korea's nuclear ambitions, but the reclusive regime conducted its first atomic test in October last year.

The six nations agreed in September 2005 to discuss furnishing North Korea with light-water reactors "at an appropriate time," with Washington insisting that Pyongyang must first disable all its current nuclear programmes.

The reactors, which generate electricity, are sought by North Korea as the impoverished nation needs a steady energy supply.

Kim also Saturday accused Japan of causing a political crisis that could lead to "disaster".

"They (Japan) are creating a political crisis worse than the financial sanctions, a crisis that infringes on our national sovereignty," Kim said.

He said he expressed his concerns to his Japanese counterpart, Kenichiro Sasae, during a rare bilateral meeting on Thursday in Beijing.

"I warned that if they take one more step forward a disaster would come," Kim said.

He refused to elaborate, but his comments came amid strong criticism from North Korea over Japan's recent forced auction of the headquarters of the pro-Pyongyang General Association of Korean Residents in Japan, or Chongryon.