Philippine President Benigno Aquino urged North Korea to scrap a planned rocket launch and focus on feeding its people, as Southeast Asian leaders prepared Wednesday to issue a statement of concern.

Aquino said experts had informed him that debris from the launch could fall in the waters off Aurora province on Luzon island north of Manila, posing a threat to populated areas in the Southeast Asian archipelago.

Aquino said the Philippine civil defence agency had been ordered to prepare for falling debris, and all flights to and from Japan and South Korea would be diverted during the expected April 12-16 launch window.

"We have to think about the safety of our people," he told reporters late Tuesday on the sidelines of a summit of the Association of Southeast Asian Nations (ASEAN) in the Cambodian capital.

"We are preparing for any eventuality... We have to prepare for the worst and hope for the best rather than prepare for the best and be totally unprepared for the worst."

ASEAN leaders are expected to issue a statement expressing concern about the proposed rocket launch at the end of the two-day summit later Wednesday.

"We will be joining in the calls for them to become more responsible... but they follow their own direction regardless of what everybody else thinks about their actions," Aquino said.

"We have been warned that debris will fall on our territory. We will emphasize the fact... that they are testing something that lands in somebody else's territory. That is not right.

"What is the message being sent to the rest of the world? They have so many problems there, they could have concentrated ... on addressing issues like food security."

Pyongyang announced last month it would launch a rocket to place a satellite in orbit, sparking alarm in the region.

The United States, Japan and other nations say the launch is a disguised ballistic missile test, and would breach a UN ban on North Korean missile launches.

Washington has suspended a plan to donate food aid to North Korea, which remains dogged by severe shortages after a devastating famine in the 1990s.

Officials cited by South Korea's Yonhap news agency have said the rocket launch will cost $850 million -- enough to buy 2.5 million tonnes of Chinese corn and feed the North's entire population for a year.