Construction is set to begin this year on a railway linking Lhasa and Nyingchi prefecture in the Tibet autonomous region with an estimated 30 billion yuan ($4.9 billion) investment, top Tibetan officials said on Wednesday in Beijing.

Lobsang Jamcan, chairman of the Tibet autonomous region, told Tibetan deputies to the National People's Congress that the government is "preparing to begin building the Lhasa-Nyingchi railway when we hold a ceremony to mark the start of operations for the Lhasa-Xigaze railway".

He said construction on the 253-km-long Lhasa-Xigaze railway that began in September 2010 is finished and that the railway is expected to begin operations this year.

Authorities have wrapped up their feasibility study on the 435-km-long Lhasa-Nyingchi railway and are ready to send it to State authorities for their review and possible approval.

Lobsang offered his own travel accounts in describing the importance of the Lhasa-Nyingchi railway.

"I traveled to the border regions at Nyingchi, Xigaze and Ali prefectures last year, and I discovered that the construction of roads and infrastructure in these regions, which are important for national security, lags far behind. Many border roads and transport facilities of neighboring India are edging closer to territory under our control."

Wangdoi, head of Nyingchi prefecture, said that the railway will help boost Tibet's goal of becoming a world tourism destination.

"Two and a half million people visited Nyingchi prefecture and spent 2.2 billion yuan last year," he said.

"Moreover, we have 200,000 people living in an area rich in resources. Poor transport conditions are creating a bottleneck for economic development in the area. The autonomous region attaches great hopes to improving people's lives," he added.

The Lhasa-Nyingchi railway can be an extension line that links Lhasa with Chengdu, Sichuan province, and can complement air and road corridors as part of a larger transport network, he said.

Wangdoi estimated the railway would need more than 30 billion yuan in investment and expected construction to stretch over three to four years. The road linking Lhasa to downtown Nyingchi is about 400 km.

Liu Xiaobin, a senior official of the National Development and Reform Commission, China's top economic planner, said the State will give "massive support" to the railway project in Tibet though he also warned that construction should be carried out efficiently.