Debris from a rocket launched by North Korea Wednesday was expected to fall off the main Philippine island of Luzon, an official said, without confirming if that had happened.

"North Korea has launched their rocket at 8:49am (0049 GMT) Philippine time. It is expected to reach our area in about 30 minutes," civil defence chief Benito Ramos said, urging fishermen to avoid the northern coast of Luzon.

"Our people should avoid the Pacific Ocean from Santa Ana (a northeast Luzon town) to Polillo island," he said in repeated radio broadcasts.

North Korea carried out the widely criticised rocket launch on Wednesday, seen by many in the international community as a disguised ballistic missile test

There was no immediate report on the success of the launch, which Pyongyang insists is a scientific mission aimed at putting a satellite in orbit.

Ramos said the Philippines did not have the technology to track the trajectory of the rocket and had asked South Korea for guidance.