The government may expand its sanctions against North Korea over its recent atomic test, Chief Cabinet Secretary Yoshihide Suga said, indicating individuals involved in Pyongyang's nuclear arms and missile programs may not be allowed to re-enter Japan.

Tokyo has already prohibited nine people from re-entering Japan after they departed for North Korea following its third nuclear test on Feb. 12. Most are senior members of a pro-Pyongyang residents' group, the General Association of Korean Residents in Japan (Chongryon).

Suga told a Diet committee Wednesday that the government is looking to expand the re-entry ban to cover individuals providing technical assistance to North Korea's nuclear arms and missile quests. Such a step would "deal a blow" to those programs, he said.

The government is separately considering joining international efforts to impose additional punishment on North Korea if the U.N. Security Council approves it, Suga said.

Japan is also studying if it can take steps in cooperation with the U.S. and without Security Council resolutions, he added, referring to sanctions on financial institutions dealing with North Korea.