Beijing: North Korea has declared the successful firing of a long-range rocket and flouted international condemnation of the launch by promising "many more".

In defiance of international warnings, North Korea fired the rocket on Sunday morning in what it said was a mission under the direct orders of lead Kim Jong-un to put an Earth observation satellite, the Kwangmyongsong-4, into orbit.

But the United Nations deplored Pyongyang's move, widely seen as part of its program to develop intercontinental ballistic nuclear missiles (ICBMs).

North Korea beamed a special announcement live on state-run television claiming the launch as a success, and trumpeted the beauty of the "fascinating vapour of Juche satellite trailing in the clear and blue sky".

It came just weeks after Pyongyang's widely-disputed claim that it had successfully tested a hydrogen bomb, and is the latest evidence of North Korean leader Kim Jong-un's willingness to ignore international pressure as tensions on the Korean Peninsula heighten.

The three-stage rocket launched from North Korea's west coast at 9am local time, and was monitored concurrently by the US, South Korean and Japanese militaries as it flew over South Korea's west coast and over the southern Japanese islands of Okinawa.

International condemnation arrived swiftly. The UN Security Council scheduled an emergency meeting for later on Sunday, with UN Secretary-General Ban Ki-moon calling on Pyongyang to halt its "provocative actions" which flew in the face of the "united plea of the international community against such an act".

Both South Korean President Park Geun-hye and Japanese Prime Minister Shinzo Abe convened emergency cabinet meetings. Both leaders described North Korea's actions as "intolerable".

Foreign Minister Julie Bishop condemned "North Korea's provocative, dangerous and destabilising behaviour".

"North Korea continues to pose a threat to the region and the globe," she said.

US National Security Adviser Susan Rice called the launch a "destabilising and provocative" action. "We call upon the international community to stand together and demonstrate to North Korea that its reckless actions must have serious consequences," she said.

Washington has persistently called on Beijing, a key trade partner on which Pyongyang relies heavily, to do more to rein in its neighbour. But China has resisted calls to leverage its economic relationship with North Korea, fearing it would back an already volatile Kim Jong-un further into a corner.

"China expresses regret that North Korea, in spite of the pervasive opposition of the international community, insisted on using ballistic missile technology to carry out a launch," the Chinese foreign ministry said in a statement on Sunday.

British Foreign Secretary Philip Hammond said North Korea's launch of a long-range rocket was a "clear and deliberate" violation of UN Security Council resolutions, .

"I strongly condemn North Korea's ballistic missile technology test ... North Korea's actions continue to present a threat to regional and international security," Mr Hammond said in a statement.

"The UN Security Council unanimously agreed to take significant measures against any further launches or nuclear tests. We will now meet with our partners in New York to agree a collective response."

North Korea sees its rocket and nuclear tests as crucial steps toward its ultimate goal of achieving a nuclear-armed long-range missile arsenal – necessary, it says, to defend itself against what it describes as decades of US hostility, and part of Kim Jong-un's "byungjin" policy of developing North Korea's nuclear program and economy simultaneously.

Pyongyang had initially told UN agencies it planned to launch its rocket sometime between February 8 and 25, before bringing the window forward to between February 7 and 14 on Saturday. It launched two hours into the revised window.

This is the sixth long-range missile test by the North in its program to develop nuclear-loaded ICBMs. It is thought to have a small arsenal of atomic bombs as well as an array of medium-range missiles but has yet to demonstrate the capability to produce nuclear warheads small enough to attach on a missile.