The original ban came into effect in October 2006 and was initially to have lasted half a year. However, owing to a lack of progress in resolving the North Korean nuclear issue, the parliament has decided to prolong the ban until October 13, 2007.
The original justification for the sanction was the nuclear weapons tests conducted by North Korea in October of 2006, at which time the Japanese authorities imposed a complete embargo on all North Korean goods and closed its ports to the Communist nation's shipping.
In early May the Japanese press published reports suggesting that the government was considering further measures against North Korea, including the possibility of a complete ban on Japanese exports there. Currently, only luxury goods and materials that could be used to produce weapons of mass destruction are subject to the embargo.
In addition, Japan may ban not only North Korean ships from its ports, but also any ships that have made ports of call there.