North Korea said Tuesday it was readying to launch a satellite, a move that the United States and its allies believe could actually be a long-range missile test that would deepen global tensions.

Just days after new US Secretary of State Hillary Clinton warned Pyongyang to avoid any provocations, the secretive country said preparations were under way for a rocket launch to put a communications satellite into orbit.

South Korea has said it regards the North's nuclear and missile capability as a serious threat and indicated a new round of sanctions would follow if the country, one of the poorest in the world, goes ahead with a launch.

Pyongyang has previously tested missiles under the guise of launching a satellite, and analysts have said recent comments from the North indicated it was on the verge of another attention-grabbing test.

"When this satellite launch proves successful, the nation's space science and technology will make another giant stride forward in building an economic power," the national space committee announced.

North Korea first tested its longest-range Taepodong-2 missile in 2006, the same year it shocked the world by testing an atom bomb, but the missile -- said to be capable of reaching Alaska -- blew up after just 40 seconds.

South Korean Defence Minister Lee Sang-Hee challenged the North to present evidence it was launching a satellite, not a missile.

"Regardless whether the North launches a satellite or tests a long-range missile, it would pose a security threat to the South as the technology involved is about the same," he told parliament.

South Korea will "trace its trajectory, assuming it is a long-range missile," Lee added.

Some analysts said the North would indeed launch a satellite but that the technology could easily be applied to a long-range missile. Experts are unsure whether it has the technology to fit a nuclear warhead to its missiles.

"If you put a warhead instead of a satellite, it's a long-range missile. The North is now seeking to show off its delivery capability," Baek Seung-Joo of the Korea Institute for Defence Analyses told AFP.

France warned the move would be tantamount to a breach of UN Security Council resolutions forbidding North Korea from any activity linked to ballistic missile technology.

"Satellite launching technology is the same as ballistic missile technology, and a North Korean satellite launch would help develop ballistic capability," the French foreign ministry said in a statement.

"We therefore call on North Korea to refrain from any gesture which could increase tension in the region and to respect its international obligations."

The North did not say when the launch would be made but Baek said it may take place around the time of the North's parliamentary elections on March 8.

North Korea sent regional tensions soaring when a missile overflew Japan's main island in 1998. At the time, Pyongyang described it as an attempt to launch a satellite.

"The primary objective is to water down UN Security Council resolutions," said Lee Chung-Min, a professor at Yonsei University.

Japan said Tuesday it was ready for any possible emergency. South Korean Foreign Minister Yu Myung-Hwan was headed to Beijing for talks with his Chinese counterpart Yang Jiechi on nuclear and missile issues.

China said it had taken note of the North's satellite launch and called for peace and stability on the Korean peninsula.

South Korea said Monday that the North had completed deployment of new medium-range missiles capable of travelling up to 3,000 kilometres (1,860 miles) -- far enough to cover most of Asia.

Years of six-party talks with the North, intended to convince the country to give up its atomic programmes, have repeatedly stalled.

The communist country has shut down its plutonium-producing complex in exchange for energy aid as part of a landmark 2007 pact agreed with its talks partners -- China, Japan, Russia, South Korea and the United States.

But negotiations on the next stage -- full denuclearisation in return for diplomatic ties with Washington and a formal peace treaty -- have been held up by disputes over how to verify its nuclear activities.