North Korean leader Kim Jong-il's health will determine when the third extraordinary congress of the North Korean Workers Party finally starts, a North Korea expert speculates. The congress is the first of its kind in 44 years.

Quoting a North Korean source, Open Radio for North Korea chief Ha Tae-kyoung on Wednesday said the congress has been delayed because the regime is looking for days when the ailing leader's health is likely to be good enough to perform his duties. In announcing the congress, the North did not name a date more specific than "early September" because it had no idea when Kim will be fit enough.

The uncertainty is causing some confusion, other North Korean sources said. Pundits say Kim, who had a stroke in 2008 and apparently suffers from diabetes and kidney failure, is resting at one of his villas.

"Kim's five-day tour of China late last month must have been a heavy strain," a South Korean security official said. "I think the regime will open the party congress only when it's sure that Kim has had a good rest."

The party congress is likely to be a grueling chore for Kim, who as party secretary will be expected to sit bolt upright in front of thousands of deputies and TV cameras at least for five hours a day and probably stand up while delivering one of the interminable speeches beloved of dictators everywhere.

In this photo taken on Aug. 14, 2010, North Koreans hold flip cards to create an image of a man and a woman during the annual Arirang Grand Mass gymnastics and artistic performance at the May Day stadium in Pyongyang, North Korea. /AP-Yonhap

The official KCNA news agency reported Kim watched a performance by the art and propaganda squad of a military unit at around midnight Wednesday, his first public appearance since his visit of China on Aug. 26-30. The unit, codenamed 963, is his personal bodyguard, and Kim has for some reason seen the same performance three times this year alone, giving rise to speculation that he is losing his faculties.

But a Unification Ministry official said Kim usually watches performances "to recharge his batteries," and in his reduced circumstances it seems he is trying to get the benefit from attending a performance by his own bodyguards not too far from where he is staying.