Tokyo  - North Korea has not gone ahead with a planned rocket launch yet, the Japanese government said Saturday, correcting earlier reports of a launch.

   Initial information about a launch had proved erroneous, Japan's NHK television said, quoting government sources.

   Japan retracted the warning about five minutes after it initially sent out the news at 12:30 (0330 GMT). Experts estimate that it takes about eight minutes for the rocket to reach Japan after being launched from its launch site at Musudan-ri in the north-east of the country.

   The Japanese Defence Ministry is investigating the reasons behind the incorrect message, but the government said the false alert was due to a still unspecified communication error in its Em-Net information-conveying system.

   North Korea has completed preparations for what it calls a communications satellite to be launched "soon," Pyongyang's official Korean Central News Agency said.

   The communist state had announced plans to launch a communication satellite between Saturday and Wednesday, but the United States, Japan and South Korea fear the rocket launch may serve as a cover for testing a long-rang ballistic missile.

   Washington and Seoul suspect Pyongyang is actually preparing to test a Taepodong-2 missile that could theoretically reach Alaska and carry a nuclear warhead. Its first test of such a missile in 2006 failed.