Chinese Foreign Minister Wang Yi held "candid" talks last week with a visiting delegation from Tokyo, the government said Wednesday after a report that the encounter involved a former Japanese premier.

The "unofficial" meeting took place Saturday, foreign ministry spokeswoman Hua Chunying said at a regular briefing.

It comes amid mounting diplomatic tensions between the two over disputed islands in the East China Sea, and with Beijing warning that any bid to shoot down its drones would constitute "an act of war", while Tokyo has accused it of jeopardising peace.

China has also been critical of Japan's new government, led by hawkish Prime Minister Shinzo Abe, who has advocated that Tokyo take a more assertive stance on the territorial dispute.

The meeting involved "senior members of the Japanese delegation attending the 9th Beijing-Tokyo forum", Hua said.

"The two sides had a candid exchange of views on China-Japan relations," she said.

"Wang Yi elaborated China's policies towards Japan and urged the Japanese government to treat the problems seriously that are hampering China-Japan relations."

Hua added that Wang "also hopes that the eminent persons from all walks of life in Japan could work hard to improve China-Japan relations".

She did not mention Yasuo Fukuda, the former Japanese prime minister, who met Wang according to Japan's Asahi Shimbun newspaper.

Fukuda, who led Japan for a year from September 2007, said in April that he briefly met Chinese President Xi Jinping at an international conference in southern China, but they did not discuss Japan-China relations.

Ties between the two countries have remained strained since a long-simmering territorial dispute over a group of islands in the East China Sea intensified last year.

Japan administers the unoccupied islands, which it calls Senkaku. China, which also claims them, refers to them as Diaoyu. The waters around them are considered potentially rich in natural resources.

Wang has extensive experience with Japan. He was China's ambassador to Tokyo from 2004 to 2007, was previously stationed there as a diplomat and speaks Japanese.