Japan said Monday it was on full alert over North Korea's planned rocket launch as a 13-day lift-off window opened, despite a suggestion from Pyongyang that it could delay the much-criticised move.

North Korea said Sunday that the launch, originally scheduled for December 10-22, could be changed "for some reasons", giving no further details.

South Korea's Yonhap news agency, citing a government official in Seoul, later said the North had stopped all preparations at the launch site in the country's northwest.

Japan has deployed missile defence systems to intercept and destroy the rocket if it looks set to fall on its territory.

"We are taking all possible measures for vigilance," Prime Minister Yoshihiko Noda told reporters as he entered his office on Monday before the launch window opened at 7:00 am (2200 GMT Sunday).

Defence Minister Satoshi Morimoto said Tokyo would keep a close eye on developments despite the comments from North Korea.

"We don't think enough changes are occurring to change our posture," he said. "We will maintain our current posture unless North Korea issues a formal notice or announcement" on the delay, he said.

Analysts said technical problems or snow, rather than overseas political pressure, are likely to be behind the delay in what the North calls a satellite launch.

The impoverished but nuclear-armed nation insists the long-range rocket launch — its second this year after a much-hyped but botched mission in April — is for peaceful scientific purposes.

But the United States, and allies South Korea and Japan, say Pyongyang plans a disguised ballistic missile test that violates UN resolutions triggered by its two nuclear tests in 2006 and 2009.

ASEAN chair urges NKorea to call off rocket launch
Phnom Penh (AFP) Dec 10, 2012 –

Cambodian Prime Minister and ASEAN chairman Hun Sen urged North Korea Monday to scrap a planned rocket launch, saying it would bring "fear and tension" to the region.

Pyongyang on Monday pushed back the window for the controversial planned launch by a week to December 29, but stressed it was pressing ahead with the mission in the face of international condemnation.

"In the name of the ASEAN chair, I appeal to North Korea to postpone the launch forever," Hun Sen said in a speech on national radio. "The launch will bring no benefits but only fear in the region and tension."

The premier said he had "the right to speak out" after foreign ministers of the 10-member Association of Southeast Asian Nations failed over the past week to reach agreement on a draft statement about the launch.

Hun Sen said his Foreign Minister Hor Namhong had been in talks with ASEAN counterparts but they could not reach "a consensus" on Cambodia's draft. He did not elaborate.

Pyongyang extended the December 10-22 window for the launch by a week due to a "technical deficiency", the Korean Committee of Space Technology said in a statement carried by the official Korean Central News Agency.

North Korea says the rocket launch is a peaceful mission aimed at putting a satellite in orbit.

The United States and its allies view it as a disguised ballistic missile test banned under UN resolutions prompted by the North's nuclear tests in 2006 and 2009.

ASEAN comprises Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam.