Vietnam estimated the cost of building a new railway linking it with China's Yunnan province at VND179 trillion (US$7.2 billion), state media reported on Wednesday last week.

The proposed 427-kilometer (265-mile) railway would extend from the northern border province of Lao Cai, pass through Hanoi, and reach both the port city of Hai Phong and Ha Long City, the Vietnam News Agency reported.

Vietnam has been seeking to upgrade its aging railway systems, including plans to build a high-speed railway running along the length of the country and lines linking with China, its largest trading partner.

The Vietnam Railway Authority had submitted the plan to build the Lao Cai-Ha Long railway to the transport ministry for review and approval, the report said.

Construction of the railway is expected to begin in 2030, it said, adding that transportation demand along this railway link is estimated at 8.3 million passengers and 17.5 million metric tons of cargo a year by 2050.

Vietnam has approached China for technology and funding for its plans to develop railways linking the two countries, which are already connected by a system of highways and two railway lines that are old and need upgrading on the Vietnam side.

The two Asian neighbours have repeatedly showed interest in boosting rail links, and recent visits to each other's countries by their leaders often included signing of agreements on railway cooperation.

Separately, Vietnam's National Assembly at a meeting on Monday this week is expected to approve a $67-billion plan to build a 1,541-km high-speed railway from Hanoi to business hub Ho Chi Minh City, the country's largest ever infrastructure project.