NANNING -- The Youyi Pass on the China-Vietnam border used to be an important military frontier, but now attracts a large number of visitors each day.

The pass is located in Pingxiang city in South China's Guangxi Zhuang autonomous region. Pingxiang is a border city in Guangxi under the jurisdiction of Chongzuo city. Its boom is attributed to the approval of the Guangxi Beibu Gulf Economic Zone (BGEZ) in 2008 by the central government.

The zone covers six cities -- Nanning, the regional capital, Beihai, Qinzhou, Fangchenggang, Yulin and Chongzuo. It has bonded areas in Qinzhou, Pingxiang, Nanning and Beihai and the China-Malaysia industrial park in Qinzhou.

In the past five years, the BGEZ has become the most vigorous area in Guangxi's economic development, as it has created one third of the region's gross domestic product, said Liang Jinrong, deputy director of the zone's planning and construction administration committee.

"The BGEZ is now a hot hub for industries, including big petrochemical projects and electric companies," said Liang.

In the first seven months of the year, foreign trade of the economic zone's four cities, Nanning, Beihai, Qinzhou and Fangchenggang, reached $7.67 billion, accounting for 45.6 percent of the region's total.

The Association of Southeast Asian Nations (ASEAN) is Guangxi's biggest trade partner, with trade volume hitting $6.14 billion in the first half of 2013, or 44.5 percent of the region's total foreign trade.

From January to July, trade between Qinzhou and ASEAN reached $570 million. Qinzhou's exports to ASEAN grew 44.6 percent to $420 million. In July alone, trade volume between Qinzhou and ASEAN hit $110 million.

"We are devoted to building a free trade port and a center of international shipping, logistics and exports processing for China-ASEAN cooperation," said Qin Kaihong, deputy head of the Qinzhou bonded area administration committee.

Hou Zhenyu, dean of the Southwest Branch of Shenzhen-based China Development Institute and expert of Beibu Gulf studies, said the country will build the zone into a "strategic pivot" for the opening up and development of the nation's southwest region.

"As China and ASEAN ties develop, the Beibu Gulf area connecting China and ASEAN, will no doubt play a greater role in opening up southwest China," he added.

The China-ASEAN free trade area was established on Jan 1, 2010.

The 10th China-ASEAN Expo will be held Sept 3-6 in Nanning.