China's top political adviser Yu Zhengsheng urged Tokyo to take "tangible action" to mend bilateral ties, during a rare high-level meeting between the Chinese and Japanese sides on Tuesday.

"China urges Japan to have a correct perception of China's growth, pursue a positive and friendly policy toward China, and deal with problems properly," Yu told visiting former Japanese prime minister Yukio Hatoyama.

They met against the backdrop of a deadlock between the two countries over territorial disputes.

Observers said non-governmental exchanges between China and Japan play an important role in maintaining communication in the absence of governmental contacts. But they added that the Japanese government needs to take more sincere measures to achieve a thaw in relations.

Yu, chairman of the National Committee of the Chinese People's Political Consultative Conference, underscored China's commitment to observing the four political documents drawn up between the two countries and to advancing bilateral strategic and mutually beneficial relations.

"It is in the fundamental interests of the two countries and the two peoples to develop long-term sound and stable bilateral relations that work for peace, stability and development in Asia and in the world," Yu told Hatoyama, of the opposition Democratic Party of Japan.

China and Japan have had few high-level political contacts since the Japanese government illegally "purchased" part of China's Diaoyu Islands in September 2012. They have not held a summit meeting since May 2012.

Hatoyama said relations between the nations face the grimmest situation since their diplomatic ties were normalized in 1972.

He called for both countries to encourage their people to understand history and to deal with problems through dialogue.

They should also increase cooperation on trade and the economy, finance and environmental protection and help build the "East Asian community", Hatoyama said.

Wang Ping, a Japanese studies researcher at the Chinese Academy of Social Sciences, said visits by friendly Japanese politicians like Hatoyama will boost both sides' confidence.

Wang said Tokyo's unilateral "purchase" of the Diaoyu Isalnds and the hawkish stance of Japanese Prime Minister Shinzo Abe have made official talks between the countries difficult.

Since taking office at the end of last year, the Japanese prime minister has tried to break the shackles of Japan's post-war pacifist Constitution and to develop a full-fledged military. He has also sought to contain China over the past year.

Huo Jiangang, a Japanese studies researcher at the China Institutes of Contemporary International Relations, said there is great potential for cooperation in the fields Hatoyama highlighted, but a breakthrough in political relations relies on the Abe administration's goodwill and concrete steps.

Hatoyama's visit is his eighth to China this year. The 66-year-old visited a memorial to the Nanjing massacre in January, and during a visit to Hong Kong last month he offered a personal apology for Japan's wartime atrocities in China, and blamed tensions in the East China Sea on Tokyo.

His latest trip to Beijing is one of several visits to China by Japanese opposition parties and non-governmental organizations.

A group of 178 executives from top Japanese companies visited last month. Despite a joint call for closer economic relations, the visit failed to break the political stalemate, Japanese media said.

Huo said Beijing has exercised restraint over the territorial issue, but Abe has not realized the consequences of an increasingly right-wing stance.