North Korea's long-range rocket should be viewed as a ballistic missile as the satellite it put into orbit is worthless, lawmakers said Sunday, citing South Korea's spy agency.

The satellite is presumed to weigh 200 kilograms, two times heavier than a satellite launched in 2012, the lawmakers said after being briefed in a close-door session by the National Intelligence Service.

A satellite weighing about 200 kilograms "is worthless as a satellite," Lee Cheol-woo of the ruling Saenuri Party said, noting a proper satellite usually weighs at least 800 to 1,500 kilograms.

Lee said South Korea presumed that North Korea has introduced key parts of a long-range missile from Russia, though he provided no further details.

The North's missile launch came a month after it carried out its fourth nuclear test. The U.N. Security Council has been working on a resolution for sanctions on the communist country.

Lee also said North Korea is preparing to conduct a fifth nuclear test at any time. (Yonhap)