BEIJING (REUTERS) - China is likely to appoint an expert on Japan and North Korea as its next foreign minister, three independent sources said, in a measure of Beijing's resolve to improve difficult relationships with two of its closest neighbours.

Barring last-minute changes, Wang Yi, 59, China's ambassador to Japan from 2004 to 2007, was likely to be appointed foreign minister during the annual full session of parliament next month, the sources said.

A fluent Japanese speaker, he was China's main representative to the six-party talks on North Korea from 2007-2008, and was a counsellor and later minister counsellor at the Chinese Embassy in Tokyo from 1989 to 1994.

"China is sending a signal that Sino-Japanese relations will be the most important of important issues," a source with ties to the leadership told Reuters, requesting anonymity to avoid repercussions for speaking to foreign reporters.

Tensions over uninhabited islands in the East China Sea - claimed by Beijing as Diaoyu and by Tokyo as Senkaku - flared last year, raising fears of a miscalculation and an unintended military confrontation.

Mr Wang was to replace Yang Jiechi, 62, who was tipped to be promoted to foreign policy tsar as one of five state councillors, the sources said. The post is senior to that of foreign minister.

The source with ties to the leadership said deteriorating ties with Japan could be improved.

"Wang Yi is like Zhou Enlai - a modest gentleman with a scholarly bearing," the source said, referring to China's first premier and foreign minister. "He will exercise restraint, is rational and wise."

The islands, also claimed by Taiwan, are one of several maritime territorial disputes involving China that have worsened as Washington shifts its security focus to Asia.

Mr Wang's two immediate predecessors were former ambassadors to Washington before taking over the foreign policy portfolio.