High speed rail lines in the country now cover some 25,000 km, equivalent to 60% of the world total.

China is set to build its first undersea tunnel for high speed trains in Zhejiang province, the media said on Friday.

The project is set to cover 16.2 km undersea area while the line will cover nearly 70 km between Ningbo and Zhoushan, reports Efe news.

Designed to run at 250 km per hour, the trains will reduce the journey time from 1.5 hours to around half an hour.

Zhejiang, which is located south of Shanghai, was one of the first regions of China to construct high-speed rail lines.

High speed rail lines in the country now cover some 25,000 km, equivalent to 60 per cent of the world total.

With projects such as the Beijing-Shanghai line - the fastest in the world with sections that reach up to 350 km per hour - or the link between Hong Kong and the national rail network, in the past few years high-speed trains have become one of the main elements of Chinese infrastructure development.