Japan is reportedly considering further sanctions against North Korea, after Pyongyang denounced a UN resolution criticising its recent missile tests.
Tokyo may ban cash remittances and freeze assets held by North Korea in Japan, according to local media.
After days of talks the UN Security Council unanimously passed a resolution on Saturday which condemned the tests.
But it was a milder document than Japan's original draft, which backed up UN demands with the threat of force.
The resolution was tabled in response to North Korea's decision to test-fire seven missiles earlier this month, including a long-range Taepodong-2, which is believed capable of reaching Alaska.
In the immediate aftermath of the test-firings, Japan imposed limited sanctions against North Korea, including a decision to ban a North Korean trade ferry from Japanese ports and a moratorium on charter flights from Pyongyang.
But according to reports in Jiji Press and the Yomiuri Shimbun newspaper, Chief Cabinet Secretary Shinzo Abe has now asked for an investigation into possible further sanctions.
These could include the suspension of cash remittances - an important source of revenue for many impoverished North Koreans with relatives in Japan - as well as a ban on bilateral trade and the freezing of North Korean assets.
Japan also plans to ask other countries to take further measures against North Korea, Kyodo News agency reported.
Japan is one of North Korea's most vehement critics - and takes a more hardline stance on Pyongyang's activities than other countries in the region.
Chapter Seven dropped
The UN resolution passed over the weekend demands that North Korea suspend its ballistic missile programme, and bars all UN member states from supplying Pyongyang with material related to missiles.
It was passed unanimously by the Security Council after being revised to drop any mention of Chapter Seven of the UN Charter, which is legally binding and can authorise military action.
The changes were made to appease China and Russia, which took a softer line than Japan and the US. China had threatened to veto the resolution in its original form.
As soon as the resolution was passed, North Korea's ambassador to the UN rejected it and left the chamber.
A day later Pyongyang angrily denounced the resolution in a foreign ministry statement, and said it would continue to build up its military arsenal.
The statement described the resolution as the product of a hostile American policy and said Pyongyang would not be bound by it, and would "bolster its war deterrent" in every way.
