Beijing hailed its friendly interaction with Japan on Tuesday after Japan's ruling and opposition parties both sent prominent envoys to China in an effort to break the diplomatic deadlock.

Observers said a major breakthrough will require a strong push by leaders from both sides, especially from Tokyo. Ties have been strained by lingering tensions over the Diaoyu Islands in the East China Sea.

Beijing on Tuesday also confirmed that Vice-Minister of Foreign Affairs Fu Ying on Monday held talks in Beijing with Kenji Kosaka, former Japanese minister of education, culture, sports, science and technology from the conservative ruling Liberal Democratic Party.

The vice-minister said China-Japan ties are now at a crucial juncture and facing a difficult situation. Fu said efforts from the Japanese community to boost cooperation are welcome, and the development of ties should avoid long-term disturbance and influence by negative factors.

"Both sides should maintain communication on how to properly handle disputes at the diplomatic level, and China is listening to voices from various channels in Japan to better handle the development of bilateral ties," Foreign Ministry spokesman Hong Lei told reporters.

Fu listened to Kosaka's ideas about Japanese public opinion on China and China-Japan ties, and she reiterated China's policy and principles regarding the development of ties.

The Japanese embassy in Beijing said Kosaka was the first lawmaker from the ruling party to visit Beijing since the conservative LDP returned to power after its landslide victory in December's lower house election.

Former Japanese prime minister Yukio Hatoyama arrived in Beijing on Tuesday. He kept a low profile and said little to reporters at the airport.

Hatoyama, a frequent visitor to Beijing who belongs to the recently ousted Democratic Party of Japan, planned to meet on Monday night with Tang Jiaxuan, former state councilor and current president of the China-Japan Friendship Association, Japan's Jiji Press News Agency said.

During his four-day visit, Hatoyama reportedly will meet key Chinese officials to exchange views on the lingering tensions between the two largest economies in Asia.

Hatoyama's visit is more of a private one, while Kosaka, the ruling party's envoy, has greater authority to reveal Tokyo's intentions these days, analysts said.

The smooth development of bilateral ties will be a great impetus for domestic economies in both countries, and despite Japan's regional policy of encircling China as well as the so-called "value-oriented diplomacy", the Abe administration knows well the importance of ties with China, said Wang Xinsheng, a professor of Japanese studies at Peking University.

Kosaka's trip, in particular, shows that the Japanese government, led by the hawkish Abe, "has not ruled out diplomatic contacts" under its framework of reining in China, Wang said.

China has long maintained friendly exchanges with various Japanese political parties, both the ruling and opposition, which "helps foster mutual understanding and boost the healthy development of bilateral ties", said Foreign Ministry spokesman Hong Lei.

Qu Xing, president of the China Institute of International Studies, said the "key" to a major improvement in ties depends on the way in which the Japanese government treats the Diaoyu Islands dispute.

"Hatoyama has previously called for an acknowledgement of the dispute over the Diaoyu Islands, a move that runs against the Japanese government's lasting stance of denying the dispute's existence. This has prompted the Abe cabinet's cold response to Hatoyama's trip," Qu said.

Japanese public sentiment regarding China has greatly deteriorated in recent years, a trend similar to the Chinese public's feeling about Japan, said Yasuko Tsuru, a professor of international politics at Chuo University in Tokyo.

Building friendships on a personal level between people of both countries is an important recipe, and "understanding each other's concerns is the first step in improving ties", Tsuru said on Tuesday, according to Japan's Yomiuri Shimbun newspaper.