Several of the Beijing-Shanghai high-speed railway's auxiliary projects have begun construction without calling for bids, which is a violation of the country's bidding rules, national chief auditor Liu Jiayi said Monday.

"These projects involve supervision, consultation and construction with a combined contract value of 4.446 billion yuan (686.64 million U.S. dollars)," said Liu.

Liu, auditor-general of the National Audit Office, made the statement in a report submitted to the 21th session of the Standing Committee of the 11th National People's Congress (NPC), China's top legislature.

A high-speed railway linking Beijing and Shanghai will officially go into operation on June 30. Construction on the railway began in 2008, with an estimated total investment of 220.9 billion yuan.