North Korea has successfully launched a rocket, boosting the credentials of its new leader and stepping up the threat the isolated communist state poses to its opponents.

It said the rocket was designed to put a weather satellite into orbit.

However, it has been labelled by the United States, South Korea and Japan as a test of technology that could one day deliver a nuclear warhead capable of hitting targets as far as the continental US.

North Korea followed what it said was a similar successful launch in 2009 with a nuclear test.

That prompted the United Nations Security Council to stiffen sanctions against Pyongyang that it originally imposed in 2006 after its first nuclear test.

The state is banned from developing nuclear and missile-related technology under UN resolutions.

However, Kim Jong-un, who took power a year ago, is believed to have continued the state's "military first" programmes put in place by his deceased father Kim Jong-il.

The launch saw the second stage of the rocket splash down in seas off the Philippines as planned.

Japan's UN envoy called for a Security Council meeting.

However, diplomats say further tough sanctions are unlikely to be agreed at the body as China, North Korea's only major ally, will oppose them.

The rocket was launched just before 1am Irish time, according to defence officials in South Korea and Japan.

The launch has surpassed a failed April launch of a rocket that flew for less than two minutes before breaking up.

There was no independent confirmation it had put a satellite into orbit.