North Korea said on Sunday it had successfully put a satellite into orbit, with a rocket launch widely condemned as a disguised ballistic missile test for a weapons delivery system to strike the US mainland.

The launch, which violated multiple UN resolutions, amounted to the North doubling down against an international community already struggling to punish Pyongyang for its nuclear test a month ago.

There was no immediate external confirmation that the final stage of the satellite-bearing rocket had successfully achieved orbit, although a US defence official said the launch vehicle "appears to have reached space."

In a special state TV broadcast, a female North Korean announcer, wearing a traditional Korean hanbok dress, said the "epochal" launch, personally ordered by leader Kim Jong-un, had "successfully put our Earth observation satellite ... into orbit."

While stressing that the launch represented the legitimate exercise of North Korea's right to the "peaceful and independent" use of space, she also noted that it marked a breakthrough in boosting national "defence capability."

Condemnation was swift, with the US calling the launch "destabilising and provocative", while Japanese Prime Minister Shinzo Abe slammed it as "absolutely intolerable."

UN emergency meeting  

In New York, diplomats said the UN Security Council would meet in emergency session later on Sunday to discuss what UN Secretary General Ban Ki-moon described as a "deeply deplorable" development.

South Korean President Park Geun-hye said the Council should respond quickly with "strong punitive measures."

The rocket, carrying an Earth observation satellite, took off at around 9:00 am Pyongyang time and, according to state TV, achieved orbit 10 minutes later.

Both South Korea and Japan had threatened to shoot it down if it encroached on their territory.

Multiple UN Security Council resolutions proscribe North Korea's development of its ballistic missile programme.

Despite Pyongyang's insistence on scientific space missions, its rockets are considered dual-use technology with both civil and military applications.

The US, along with allies like South Korea and Japan, had warned Pyongyang it would pay a heavy price for pushing ahead with launch, but analysts said the North's timing was carefully calculated to minimise the repercussions.

With the international community still struggling to find a united response to the North's January 6 nuclear test, the rocket launch - while provocative - is unlikely to substantially up the punitive ante.

"North Korea likely calculates that a launch so soon after the nuclear test will probably only incrementally affect the UN sanctions arising from that test," said Alison Evans a senior analyst at IHS Jane's.

China's 'regret'  

North Korea's chief diplomatic ally, China, which has been resisting the US push for tougher sanctions, reacted briefly to the launch with a simple expression of "regret."

While infuriated by North Korea's refusal to curb its nuclear ambitions, China's overriding concern is avoiding a collapse of the regime in Pyongyang and the possibility of a US-allied unified Korea on its border.

North Korea last launched a long-range rocket in December 2012, placing a similar Earth observation satellite in orbit.

Western intelligence experts say that satellite has never functioned properly, fuelling suspicion of the mission's scientific veneer.

Despite Pyongyang's bellicose claims to the contrary, the North is still seen as being years away from developing a credible inter-continental ballistic missile (ICBM).

A key challenge it faces is mastering the re-entry technology required to deliver a payload as far away as the US.

"An ICBM warhead, unlike a satellite, needs to come down as well as go up," said aerospace engineer John Schilling, who has closely followed the North's missile programme.

"North Korea has never demonstrated the ability to build a re-entry vehicle that can survive at even half the speed an ICBM would require," Schilling said.

"If and when they do, what is presently a theoretical threat will become very real and alarming," he added.