North Korea could bring about its own collapse if it keeps pouring resources into nuclear and conventional weapons, South Korea's national security adviser said in an interview to be screened Monday.

Chun Yung-Woo argued in the interview with US public broadcaster PBS that the Pyongyang regime faces so severe an economic crisis that it could collapse sooner than expected.

The "energy for change is growing" and will reach "critical mass" at some point in the impoverished communist state, he said in excerpts posted on the PBS website.

"We have shut down major channels of cash flow annually into North Korea" through sanctions, Chun said, adding that the North's continued spending on military capabilities "would be a short-cut to their demise".

South Korean officials rarely comment publicly on the prospect of the regime's downfall in the communist North, although President Lee Myung-Bak has been stressing the need to prepare for reunification.

Chun said the North could not resolve its "existential" economic problems -- which include chronic food shortages -- on its own. The country is in a dire state of economic collapse exacerbated by severe flooding last year.

"But the only way they can obtain massive outside assistance, which will be enough to turn the tide around, is denuclearisation," Chun said.

The foreign ministry said Chun's comments do not indicate a new stance.

The South's "North Korea policies are not based on any assumption about the North's potential collapse, and (we) are seeking practical reconciliation and cooperation through dialogue", said spokesman Kim Young-Sun.

China's President Hu Jintao, in a written interview with the Washington Post and the Wall Street Journal before this week's visit to Washington, called for an early resumption of six-party talks on the North's nuclear disarmament.

The talks -- chaired by China -- also group the two Koreas, the United States, Russia and Japan.

But South Korea insists it will not resume dialogue with the North, despite several recent approaches from Pyongyang, until it accepts responsibility for attacks in recent months and expresses regret.

The North on November 23 bombarded a South Korean border island, killing two Marines and two civilians.

The United States and South Korea also accuse it of torpedoing a South Korean warship last March with the loss of 46 lives, a charge it denies.

Kim said Seoul is closely watching Hu's visit and coordinating its policies on Pyongyang with Washington.

What is most important is to see a "sincere change of stance" from the North, he told a briefing.

"In this regard, we hope that the Chinese government...will play a responsible role in (keeping) peace, stability and denuclearisation of the region."