Several high-ranking North Korean officials have defected to the South as Pyongyang struggled with an "increasingly chaotic situation", said a US diplomatic cable released on the WikiLeaks site.

The cable -- written by the US ambassador to Seoul in January -- also quoted South Korea's foreign minister as saying that the defections by officials based overseas "have not been made public".

Foreign Minister Yu Myung-Hwan had asserted that the succession from leader Kim Jong-Il to his son Jong-Un, 27, was "not going smoothly" and that a botched currency reform had caused "big problems" for the communist regime.

The cable is the latest in a torrent of leaked US diplomatic communications by the whistle-blowing website WikiLeaks that have left the United States red-faced and scrambling to limit the international fallout.

Interpol on Wednesday issued a global arrest warrant for WikiLeaks founder Julian Assange, 39, who is wanted in Sweden for questioning over the alleged rape and molestation of two women. Assange has denied the charges.

South Korea's foreign ministry and intelligence agency Wednesday declined to confirm the authenticity of the material, which was marked "confidential".

The report by US ambassador Kathleen Stephens said Yu had predicted that Kim Jong-Il would visit China within weeks -- a trip he indeed made, albeit months later, in May, followed by another visit in August.

Yu asserted that "the North Korean leader needed both Chinese economic aid and political support to stabilize an 'increasingly chaotic' situation at home," the American ambassador wrote.

"In particular, FM Yu claimed that the North's botched currency reform had caused 'big problems' for the regime and that the power succession from KJI (Kim Jong-Il) to Kim Jong-Un was 'not going smoothly'," she wrote.

"Moreover, Yu confided, an unspecified number of high-ranking North Korean officials working overseas had recently defected to the ROK. (Note: Yu emphasized that the defections have not been made public. End note.)"

Yu also said Seoul planned to help combat tuberculosis "which has spread widely within the DPRK's chronically malnourished population", the cable said, using the country's official name the Democratic People's Republic of Korea.

The foreign minister made his comments in a January 11 meeting with US special envoy for North Korean human rights issues Robert King.

Yu also said the number of North Koreans fleeing to neighbouring China, which arrests and repatriates them if caught, would "continue to increase" in 2010 amid chronic food shortages and other hardships.

More than 20,000 North Koreans have managed to escape via third countries to the South, with a record 2,927 arrivals last year.