Japan launched a new spy satellite into orbit Monday amid concerns over North Korea's missile programme and to monitor natural disasters in the region, officials said.

The Japanese H-2A rocket carrying an information-gathering radar satellite lifted off at 10:21 am (0121 GMT) from the Tanegashima Space Center in southwestern Japan.

"The rocket was launched successfully," said Toshiyuki Miura, a spokesman for Mitsubishi Heavy Industries, which built the satellite and worked on the launch with the Japan Aerospace Exploration Agency (JAXA).

"The satellite was separated into orbit around the Earth later," Miura added.

The government decided to build an intelligence-gathering system after North Korea launched a missile in 1998 that flew over the Japanese archipelago and into the Pacific, shocking many in Japan.

In defiance of international pressure, North Korea launched what was believed to be a three-stage Taepodong-2 missile in April 2009, with an estimated range of 6,700 kilometres (4,100 miles).

Japan has three operating optical satellites. Two radar ones were successfully placed into orbit but both broke down later. Another optical satellite was launched in September but is not yet functioning.

Demand for land surveillance grew meanwhile after Japan's March 11 quake and tsunami, which killed some 20,000 people and crippled cooling systems at the Fukushima Daiichi nuclear plant, northeast of Tokyo, causing reactor meltdowns.

"The project is aimed at boosting security and monitoring land in case of sizable natural disasters like the one in March," a government official said, adding that the current three satellites were used to track the March calamity.

"If everything goes smoothly, it will be the first radar satellite under the programme," the official said. "With the radar satellite, we can introduce wider usage of the system."

Radar satellites are able to capture images at night and in cloudy weather, something that optical satellites cannot.

The latest satellite cost some 39.8 billion yen ($512 million) to develop, while the launch cost about 10.3 billion yen, Kyodo News reported.

JAXA and Mitsubishi Heavy had originally planned to launch the satellite on December 11 but it was postponed due to bad weather.