North Korea's missile programme represents a serious threat to world security because Pyongyang could link it with its nuclear programme, South Korean Foreign Minister Yu Myung Hwan said Wednesday, dpa reported.
He also warned the North that it faced international sanctions if it again carries out a launch.
"North Korea's missile is not a mere conventional weapon," Yu was quoted as saying by the national news agency Yonhap at a meeting in Seoul with foreign diplomats. "The combination of its long-range missile and nuclear capability will have a very serious impact on the world's peace and security."
South Korean officials have said that North Korea has been planning a launch of its Taepodong-2 intercontinental ballistic missile for weeks.
On Monday, North Korea admitted for the first time that it was readying the launch of a multiple-stage rocket but said it was for "space development."
Whether the North launches a satellite or missile, such an incident would represent a violation of UN resolutions, Yu said.
A missile test or satellite launch is not very different from a technical point of view, he argued, and either would "certainly" lead to sanctions.
A resolution adopted by the United Nations in 2006 after a series of North Korean missile tests demanded the country halt its ballistic missile programme, and included economic sanctions.
South Korea has speculated that North Korea is preparing to test a Taepodong-2 missile under the guise of a satellite launch, as it did in 1998 when it fired a Taepodong-1 over Japanese territory.
According to the US military, the Taepodong-2, when technically perfected, could reach the US state of Alaska and carry a nuclear warhead.