Premier Li Keqiang will embark on his first trip to the Southeast Asian nations closely following President Xi Jinping's visit to the region, a high frequency experts say shows Beijing's "unprecedented emphasis" on nurturing good relationship with its neighbors.

From Oct 9 to 15, Li will attend the East Asia leaders' meetings in Brunei, the chair nation of the Association of Southeast Asian Nations, and pay official visits to Brunei, Thailand and Vietnam.

The visit will be the premier's first trip to the Southeast Asian nations after assuming office in March, and Vice-Foreign Minister Liu Zhenmin told reporters on Monday the seven-day tour is "an important installment" in China's diplomacy with its neighbors.

Meetings during Li's trip to Brunei include the 16th China-ASEAN leaders' meeting, the 16th ASEAN plus three (China, Japan and the Republic of Korea) summit and the 8th East Asia Summit.

Li's tour tightly follows President Xi Jinping's visits to Indonesia and Malaysia from Oct 2 to 8.

Wu Shicun, head of the National Institute of South China Sea Studies, said visits by the president and the premier will cover five nations and span two weeks, which demonstrates the great priority placed by the new leadership on diplomatic strategy.

"The China-ASEAN relationship has entered a brand-new era. In the past, most attention was paid to economic and trade cooperation but, these days, more focus is also on politics and security," Wu said.

This year marks the 10th anniversary of the China-ASEAN strategic partnership and the two sides have established "the largest free trade zone among developing nations", Liu said.

The past 10 years have seen bilateral trade surge from $78.2 billion to more than $400 billion. Bilateral investment has surged from $33.2 billion to $100 billion.

The premier will introduce the new Chinese leadership's policies to develop the country's relationship with ASEAN and outline future cooperation during the 10+1 leaders meeting.

The 10+1 meeting will release a joint statement to commemorate the 10th anniversary of the China-ASEAN strategic partnership.

At the 10+3 summit, Li will present Beijing's views and positions on how to jointly weather the storm of the global financial crisis and improve pragmatic cooperation, Liu said.

When Li visits Brunei from Oct 9 to 11, the two countries will release a joint statement and sign cooperation contracts. Bilateral trade between the two has reached $1.61 billion and achieved $870 million in the first half of this year.

"The good relationship and cooperation between Brunei and China will improve further in several sectors, including agriculture, fisheries, energy and economic sectors," Chinese Ambassador to Brunei Zheng Xianglin told Xinhua News Agency.

The premier will make a speech at Parliament when visiting Thailand from Oct 11 to 13.

Li's visit to Hanoi will be the first one made by the new Chinese leadership, Liu of the foreign ministry said.

Beijing and Hanoi have maintained frequent high-level contact and interaction this year although the relationship has been overshadowed by some maritime incidents and Vietnam's claims regarding the South China Sea in the past few years.

The party chiefs of the two countries talked by hotline in March and Vietnamese Prime Minister Nguyen Tan Dung visited Beijing in June. The Vietnamese president attended the China-ASEAN Expo in September in Nanning.

The two sides will properly handle the South China Sea issue and exchange views on deepening the China-Vietnam comprehensive strategic partnership, Liu said.

Ruan Zongze, vice-president of the China Institute of International Studies, said a cooperative and friendly trend is overwhelming in the region, but destabilizing factors and challenges also remain.

The Philippines and Vietnam have in recent years attempted to impose their territorial claims on some of the islands in the South China Sea into the agenda of ASEAN high-level meetings.

Such members of ASEAN are "acting out of their own interests and even seeking help from forces outside the region", Ruan said.

"The world economy is still faced with difficulties when striving to achieve recovery, and realizing robust growth in the East Asian region requires a closer cooperation and interaction between China and Southeast Asia countries," Ruan said.