Japan and China have also experienced rising tension over lucrative disputed gas fields as well as Beijing's campaign to block Tokyo's bid for a permanent seat on the UN Security Council.

Despite the tension, the two countries' economies have become increasingly interlinked, with China now Japan's biggest trading partner.

Wu signalled that Beijing was in no rush to settle the dispute over the area in the East China Sea, where Japan alleges that China may be siphoning gas.

"We are considering where we should carry out joint development, but it's better to allow ample time for discussions," Wu said.

Wu, who is China's lead negotiator in six-nation talks on ending North Korea's nuclear weapons program, also voiced concern about the long stalemate in negotiations.

"The talks are in a difficult phase," he said. "It is dangerous to be in such a difficult phase, as it may have various implications."

North Korea has boycotted talks since November to protest US financial sanctions on a Pyongyang-linked bank.

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