Quoting unspecified government sources, Kyodo news agency said the government planned to revise the law to include harsher punishments for violators. Tokyo was also seeking stricter controls on exports of machinery that could be used to develop nuclear weapons and other weapons of mass destruction, the sources were quoted as saying.
The government wanted to have the legislation passed during a parliamentary session opening on Thursday, they said. Japanese government officials were not immediately available for comment.
The report follows North Korea's agreement to return to six-party talks aimed at coaxing it into scrapping its nuclear weapons plans. US officials expressed hope last week of making progress in the nuclear standoff.
After Pyongyang test-launched seven missiles on July 5 and conducted a nuclear test on October 9, Tokyo slapped its neighbour with a package of sanctions.
Punitive steps included banning visits by a North Korean ferry long suspected of involvement in transporting parts for North Korea's missile programmes.
In November, Japan banned exports of luxury goods to the North in a move experts said was aimed at the ruling elite, whose lavish lifestyle is in stark contrast to that of most citizens of their impoverished state.
Following Pyongyang's nuclear test, the United Nations Security Council approved a resolution that, among other measures, blocks trade with North Korea in luxury goods.