All loopholes must be closed in electing deputies to people's congresses to prevent such frauds as the one found in Hengyang City, China's top legislator Zhang Dejiang said Sunday.

Investigation showed that 56 lawmakers from Hengyang City in central China's Hunan Province bribed 518 fellow municipal lawmakers and 68 staff to be elected to the Hunan provincial people's congress. The fraud is record-making in terms of the number of people and the quantities of money which exceeded 110 million yuan (18 million U.S. dollars).

The case of vote buying in Hengyang was severely dealt with in accordance with the law and the codes of discipline, said Zhang, chairman of the Standing Committee of the National People's Congress (NPC), while delivering a work report at an annual session of the NPC.

"We must take this profound lesson to heart, and improve relevant institutions to close all loopholes," he said.

"We must effectively strengthen the Communist Party of China's leadership over the election of deputies to people's congresses, be strict in the election of deputies, follow procedures strictly in accordance with the law," he said.

The country must also make full use of the role of the standing committees of people's congresses at all levels, improve the mechanisms for reviewing deputies' qualifications, and tighten oversight over the whole process of electing deputies in order to ensure that elections are carried out honestly, he added.