China's railways minister, a key figure behind the investment boom in the sector, has been dismissed after he was under investigation for "serious disciplinary violations", the official Xinhua news agency reported.

"The Standing Committee of the National People's Congress, the top legislature of China, on Friday decided to dismiss Liu Zhijun from the position of railway minister and appointed Sheng Guangzu as the replacement," Xinhua said, but did not provide any more details.

Xinhua said two weeks ago that Liu, who was stripped of his position as Communist Party chief at the ministry, was under investigation for "serious disciplinary violations", without elaborating. The term "serious disciplinary violations" usually results in criminal charges.

Liu's replacement, Sheng, is the head of the customs administration.

Liu has been China's railway minister since 2003 and has spearheaded the investment drive into the sector over the last decade.

China is in the midst of a massive investment programme to build a faster and bigger railway network. The government plans to spend $120 billion a year, over several years, on railway construction.

Liu's brother, Liu Zhixiang, was given a suspended death sentence in April 2006 for a long list of crimes, including hiring an assassin, bribery and embezzlement of funds. (Reuters)