Many North Korean engineers had stayed in Libya for years to develop missiles, the conservative Sankei Shimbun reported, citing an unnamed source close to the matter, adding that Iran also had about 100 military-related contracts with the country.
The newspaper said Libya had signed an agreement under which it would pay for North Korean and Iranian engineers to provide technical assistance to develop weapons of mass destruction.
The report came after Libya announced last month that it would dismantle its weapons of mass destruction programs and allow international inspections of its nuclear facilities.
The Sankei said the announcement might allow inspectors to study the military technology of North Korea and Iran.
It said North Korea has long provided technical assistance to Libya to develop Scud missiles, adding that the two nations had also been discussing the development of North Korean Rodong missiles in Libya.
The report said Iran had built a fuel plant for Scud missiles in Libya and had built and operated three missiles parts plants there.
Iran also helped improve the capability of Libya's Scud missiles and other missiles for Libya and held training for Libya's missile engineers.