From 1 July several high-speed railway lines, including those linking Wuhan and Guangzhou, Zhengzhou and Xian, and Shanghai and Nanjing, will reduce train speeds from 350kph to 300kph.

The move is consistent with a nationwide directive made public in April that stated all high-speed trains must run at a slower pace than previously announced.

The directive followed a corruption scandal in February when railways minister Liu Zhijun was dismissed after an investigation into serious disciplinary violations. It raised concerns over the costs and safety of high-speed rail links.

Deputy railways minister Hu Yadong rejected speculation that operating speeds had been reduced because high-speed railways were unsafe or unreliable. He said that the decision was taken to maximising efficiency.