The Sankei's report followed an article in the Yomiuri Shimbun, another Japenese newspaper, a day earlier saying that North Korea has ordered its overseas diplomats to be prepared for an "important announcement" within a few days.
The Yomiuri Shimbun reported, quoting several unidentified sources familiar with North Korean issues, that Pyongyang had told diplomats around the world to refrain from travelling until the announcement had been made.
The sources suggested that the message could be related to Kim's health or the communist nation's relations with South Korea.
Kim's failure to appear at North Korea's 60th anniversary parade on September 9 sparked widespread conjecture that he was ill or even dead.
South Korean officials have said that he underwent brain surgery following a stroke around mid-August. Some reports said that Kim has suffered partial paralysis.
However, North Korean state television last week broadcast photographs which it said were of a recent inspection by Kim of a women's artillery base.
|Kim's absence from the country's 60th anniversary parade sparked rumours [EPA]
Pavel Felgenhauer, a Moscow-based military analyst, told Al Jazeera that there would probably be a power struggle in North Korea if it was announced that Kim had died.
"When the father of Kim Jong-il died there was a smooth transition because there was a clear heir to the throne. Now there isn't and there is a high possibility of a destabilisation of Korea," Felgenhauer said.
"There are the military leaders who are very powerful, there is also the Kim family that is very powerful, clearly there are going to be divisions.
"For North Korea right now reunification right now would be like the reunification of Germany; the disapperance of a Stalinist communist state, and of course the leadership is totally against that."
"There could be again a crisis between the South and North, although hopefully this will just be the closing of borders and in a year or so they will go again for some kind of detente."
Kim 'in control'
Lee Sang-hee, South Korea's defence minister, said on Friday that he believed that Kim remained in control in Pyongyang despite the widespread reports, but that the situation in North Korea was unpredictable.
"Kim Jong-il has not been seen in public for a while now," he said.
"But both Korean and United States intelligence services estimate that he still has control over his administration."
Lee said the state of Kim's health had "significant implications for the security of the Korean peninsula.
"Crisis or instability situations in North Korea could stem from many different causes, so it would be very difficult to predict them at this point".