SEOUL, South Korea — For weeks, North Korea watchers have been awaiting what would be the biggest political gathering there in decades: an announced meeting of the reclusive state’s ruling Workers’ Party in “early” September to select the party’s top leadership.

The first half of the month passed Wednesday without any sign that the meeting had taken place, intensifying speculation that something was amiss.

The meeting would not be routine. The North Korean leader, Kim Jong Il, would be bringing together party delegates in the capital, Pyongyang, for the first time in 30 years. That has generated conjecture that he might use the event to help his third son, Kim Jong Un, make his debut as the country’s future leader.

“There are good reasons to suspect that something in Pyongyang went wrong again, and the longer the delay is, the greater the scale of these unknown problems is likely to be,” said Andrei Lankov, a North Korea expert at Kookmin University in Seoul. “Even if the conference will open among the usual pomp later this week, the inability or unwillingness to convene it as initially scheduled still should not be ignored.”

Several analysts cited recent severe floods as a possible factor.

Good Friends, a Buddhist relief agency that says it has informants inside North Korea, said in a newsletter Wednesday that the party meeting had been postponed because flood-damaged roads and communication lines prevented the government from gathering enough delegates.

The South Korean unification minister, Hyun In-taek, said: “It may be because of the flooding, or there could be various other reasons. There appear to be internal reasons.”

Cheong Seong-chang, an analyst at Sejong Institute, south of Seoul, said, “Kim Jong Il must have considered it a big burden to stage a major political event for his son’s debut while people lost lives and homes.”

Kim maintains such secrecy that analysts often rely on unconfirmed news accounts, secondhand information relayed through recent defectors and occasional intelligence reports to make often conflicting conjectures.

When Kim was rising to power decades ago, speculation raged as to whether his father, President Kim Il Sung, would eventually hand over power to his son and whether the son, depicted as a hard-drinking womanizer in media outside North Korea, was capable of leading the country.

Now, similar speculation and skepticism abound about Kim Jong Un. His sudden appearance in the North’s succession game a few years ago set media outside the North scrambling to a Japanese chef who once cooked for the Kim family and to former classmates at a Swiss school where the younger Kim once studied.

But little is known about the son. Analysts vary widely over whether he would get prominent party posts in the party meeting or, even if he were made Kim Jong Il’s successor, how long he would last once his father died. Kim Jong Il is believed to have had a stroke in 2008.

Amid the information blackout, the delay in the party meeting is feeding imaginations. The South Korean media had earlier speculated that North Korea delayed the conference because Kim’s health deteriorated after he made a trip to China late last month, or because not all the power elite was happy with the choice of Kim’s successor.

Kim Yong-hyun, a North Korea expert at Dongguk University in Seoul, doubted those reports. He noted that Kim apparently was still active in his tours of factories and farms and that his grip on power precluded any serious challenge to his decisions.

A far bigger challenge for Kim — and another possible cause of the delay — was the task of persuading party representatives gathering after such a long hiatus that he and his son would fix the economy and ease chronic food shortages, said Kim, the Dongguk analyst.

Whatever the reasons, “one thing seems to be fairly certain,” Lankov said. “Something unusual is happening in Pyongyang these days.”

© 2010 The New York Times Company