One of the planned lines would run from Vietnam's port cities of Haiphong and Quang Ninh through Hanoi to Lao Cai province, which borders China's Yunan province, the ministry said late on Tuesday.

The other would run from Hanoi to Lang Son province, which borders China's Guangxi region, passing through an area densely populated with global manufacturing facilities, including some owned by Chinese investors.

(Reporting by Khanh Vu; Editing by John Mair)