Japan's foreign minister told US Secretary of State Condoleezza Rice on Wednesday that the world must not close the door on diplomacy with North Korea, an official said.
Japan has strongly backed the US push to enforce sanctions on North Korea, which last week said it tested its first atom bomb.
But Foreign Minister Taro Aso, meeting with Rice at the start of her four-nation tour of North Korea's neighbours, said that diplomacy remained the goal.
"The objective is not sanctions in themselves -- it's an end to its nuclear program," Aso told Rice, as quoted by a Japanese foreign ministry official present at the talks.
"So we should keep open the window of dialogue and call for the unconditional resumption of six-party talks," Aso was quoted as saying.
North Korea walked out of six-nation talks nearly a year ago in protest of US sanctions on a bank accused of laundering and counterfeiting money for the regime.
The talks had just two months earlier reached an agreement in general terms for North Korea to give up its nuclear arsenal in exchange for security and aid guarantees.
The White House has rejected calls for direct talks between the United States and North Korea, saying Washington would stick with the six-party negotiations that also group North and South Korea, China, Japan and Russia.