A high-speed railway that will cut travel time between Beijing and Shanghai to around four hours will open in June, a year ahead of schedule, state media said Tuesday.

China also plans to invest 700 billion yuan (106 billion dollars) in railway construction this year, railways minister Liu Zhijun was quoted by the official Xinhua news agency as saying.

Work on the fast rail linking Beijing and Shanghai started in April 2008 with a planned investment of 220.9 billion yuan. The line was originally scheduled to open in 2012.

Once operational, the line is expected to carry 80 million passengers a year - double the current capacity on the 1,318-kilometre (820 mile) route, which currently takes 10 hours, previous state press reports have said.

China's high-speed rail network will reach 13,000 kilometres this year compared with 8,358 kilometres at the end of last year, Liu said.

Beijing previously announced a rail development programme aimed at increasing the national network to 120,000 kilometres by 2020, making it the most extensive rail system outside the United States.

But Liu said the goal would be achieved in five years after the total length of the country's rail network reached 91,000 kilometres at the end of 2010.