Senior officials in Hunan Province have been expelled from the Communist Party of China (CPC), removed from their posts and transferred to judicial organs for dereliction of duty, for major electoral fraud involving over 500 lawmakers, CPC discipline watchdogs said on January 2.

Tong Mingqian, then Party chief of Hengyang in Hunan Province, was in charge of the election a year ago but did not take effective measures to crack down on bribery during the election process, the CPC Central Commission for Discipline Inspection (CCDI) said in a statement on its website.

Tong was sacked from his new post as vice chairman of the Hunan Provincial Committee of the Chinese People's Political Consultative Conference on December 21.

The Supreme People's Procuratorate (SPP) on Thursday decided to investigate Tong and put him under "compulsory measures" during the investigation, according to its statement.

Compulsory measures include arrest, release on bail and residential surveillance. The SPP statement did not explain which compulsory measures were imposed on Tong.

The electoral fraud scandal was made public on Saturday, while the election took place from December 28, 2012 to January 3, 2013.

Preliminary investigation shows 56 lawmakers from Hengyang who were elected to the Hunan provincial legislature offered bribes to 518 city lawmakers and 68 staff. Total bribes exceeded 110 million yuan ($18.14 million).

The electoral fraud inflicted great losses to the interests of the Party, the country and the people, and left a harmful political and social impact, according to the CCDI statement.

"Tong would be accused of the crime of dereliction of duty, which can be punished by up to seven years in jail. However, the sentence might be longer if he took bribes," Ruan Qilin, a criminal law professor at the China University of Political Science and Law, told the Global Times.

If a civil servant's dereliction causes damage to public assets or the reputation of  the government, he or she could be charged for the crime of dereliction of duty based on Criminal Law. If the dereliction was associated with bribes, the sentence can be up to 10 years. 

The provincial CPC discipline watchdog also announced on Thursday that a local senior lawmaker, Hu Guochu, has been passed on to judicial authorities for suspected dereliction of duty and accepting bribes in the electoral fraud.

Hu has been arrested and Hunan Provincial People's Procuratorate launched an investigation toward him, according to their official website on Thursday.

Xinhua contributed to this story