Japan's coast guard on Tuesday began issuing warnings to ships in the area to be on the lookout for falling debris from North Korea's planned rocket launch.

"We are announcing by radio the expected time and places where falling objects could appear," coast guard spokesman Yoshiyuki Terakado said.

Coast guard officials will issue the warning every day in Japanese and English until the launch is confirmed, he said.

Poor but nuclear-armed North Korea attracted international condemnation after it announced a plan to launch a satellite sometime from April 12 to 16, to mark the centenary of the birth of late founding president Kim Il-Sung.

Pyongyang insists the launch is a peaceful space project but the United States and its allies view it as a disguised missile test in breach of UN resolutions.

Japan has deployed missile defence systems to intercept and destroy the rocket if it looks set to fall on the country, a move similar to measures the country took in 2009 before Pyongyang's last long-range rocket launch.

S. Korea, US defence chiefs discuss N. Korea rocket
Seoul (AFP) April 10, 2012 - South Korean and US defence chiefs vowed Tuesday to take coordinated action in the face of North Korea's planned rocket launch, calling it "a grave provocation", the defence ministry said.

Defence Minister Kim Kwan-Jin and US Defence Secretary Leon Panetta agreed in their telephone conversation to forge close cooperation against the launch and maintain a strong defence posture, the ministry said.

"Both ministers shared the view that North Korea's long-range missile launch is a grave provocation," it said in a statement without disclosing what action was envisaged.

The poor but nuclear-armed North attracted international condemnation after it announced a plan to launch a satellite sometime from April 12 to 16, to mark the centenary of the birth of late founding president Kim Il-Sung.

Pyongyang insists the launch is a peaceful space project but the United States and South Korea view it as a disguised missile test in breach of UN resolutions.

South Korea has vowed to shoot down the rocket if it strays into its territory. Japan has said it may do likewise.

The South's military plans to deploy destroyers armed with missiles to the Yellow Sea to track the rocket.

The transport ministry said it would provide up-to-date information to shipping on the rocket launch.

All 15 maritime traffic control centres will be placed on alert from Wednesday, issuing navigation warnings every two hours to protect vessels operating in the Yellow Sea, it said.

The first stage of the rocket is expected to fall in waters 170 kilometres (100 miles) west of Gunsan in the southwest of South Korea, it said.