Japan says it is imposing sanctions on North Korea after a satellite launch seen by Washington and its allies, including Tokyo, as cover for development of ballistic missile technology that could be used to deliver a nuclear weapon.
The news on Wednesday (local time) followed South Korea's announcement that it would suspend operations at a jointly run factory park just inside North Korea, in a move to cut off an important source of revenue for the impoverished North.
Chief Cabinet Secretary Yoshihide Suga told a news conference that remittances of money to North Korea would be forbidden, except for sums less than Y100,000 ($A1,233) intended for humanitarian purposes.
Japan will also tighten curbs on travel with North Korea, and ban all port calls by North Korean ships, even for humanitarian purposes, as well as visits by third-country ships that have made port calls on the North.
"North Korea conducted the fourth nuclear test in defiance of calls for self-restraint from the international community, and then pushed ahead with the launch of a ballistic missile," Suga told a news conference.
"This poses a direct and serious threat to the safety of our country, significantly hurts the peace and safety of northeast Asia and the international community, and is absolutely unacceptable."
Japan eased some sanctions on North Korea in July 2014 in return for Pyongyang reopening an investigation into the fate of Japanese citizens abducted decades ago by North Korean agents to help train spies, although little progress has been seen since.
Despite the fresh sanctions, Japan intends to keep open its dialogue with North Korea to resolve the abduction issue, Suga said.
Pyongyang admitted in 2002 to kidnapping 13 Japanese citizens decades earlier. Five abductees and their families later returned to Japan but Tokyo wants to know the fate of the remaining eight, who Pyongyang has said are dead, and others Japan believes were also kidnapped.