Beijing will open a new subway line and complete the extension of an existing line in May, the latest move to improve transport infrastructure in the southern part of the city, municipal authorities said.

The first phase of Line 14, and the last two stations to complete the circular Line 10, will begin operation on May 5, said Lu Zongcun, a senior planner of Beijing MTR Construction Administration Corp, which builds Beijing's subway lines.

The western section of Line 14 will be operational in time to service crowds attending the 9th China (Beijing) International Garden Expo, which is scheduled to begin on May 18, Lu said on Friday.

One of the line's seven stations will be named Garden Expo Station, and the line will connect Beijing's Fengtai district to the downtown area, with its 12.4-kilometer track.

The last two stations of Line 10, Fengtai Station and Niwa Station, will open in May. Once completed, Line 10 will operate in a full circle, becoming Beijing's second subway loop line and the longest line in the city, according to the city's transport authority.

The southern area of Beijing has long been the poorer side of town, with weaker transport infrastructure. In 2010, the municipal government launched a three-year plan to boost development of the area, including measures to improve transport.

According to a statement from the municipal government, five new subway lines, including the Daxing and Yizhuang lines, have opened in the past three years, increasing the length of subway lines in the southern area to 118 km.

Before the development plan, only two subway lines, Line 4 and Line 5, serviced the capital's southern suburbs.

Extending the subway lines has improved transport in southern parts of the city. Data from the Beijing Mass Transit Railway Operation Corp showed that on Friday, 184,000 trips were taken on the Yizhuang Line and 309,000 on the Daxing Line. But there have been complaints from commuters in online forums that transportation in southern parts of the city still lags behind services provided in the north.

Xiao Fang, a resident of Yizhuang, said the subway stations are often overcrowded.

"So many people take the Yizhuang Line every day. During rush hours I sometimes can't get on the train. The 7-minute interval between trains on the line is also too long," he said.

Xiao said he hopes the government will extend the operation times of the Yizhuang Line.

This year, Beijing will start construction on three new lines - the third phase of Line 8, Line 16 and the Yanfang Line, with most stations located in southern parts of the city, said Lu.

He said planning and design work on the New Airport Express, a line connecting Beijing's urban area to the new airport in the southern Daxing district, will begin this year.

In 2013, Beijing will start a new three-year plan for its southern area. By the end of 2015, the city will have 13 subway lines servicing residents in the area, with total length of those subway lines reaching 225 km, according to Beijing Evening News.

According to a statement from the municipal government, under the development plan the construction of six main roads connecting the southern and downtown areas is also under way.

jinhaixing@chinadaily.com.cn