China's courts handled a rapid rise of corruption cases last year as the country maintained high pressure against graft.

A total of 45,000 graft-related cases were heard by courts at all levels last year, with about 63,000 people convicted, Chief Justice Zhou Qiang said while giving a work report to the annual session of the National People's Congress, the top legislature.

Both numbers were up by about 30 percent compared with figures he gave in last year's report.

Prosecutors brought public charges against 48 officials at or above ministerial level - including Ling Jihua and Su Rong, both former vice-chairmen of the country's top political advisory body - and started probing 21 other such senior officials, said Procurator-General Cao Jianming.

Procurators also investigated 17,410 lower-level officials suspected of corruption in land expropriation and demolition, social security, management of agriculture-related funds and other issues concerning the people's well-being, he said.

Both the chief justice and procurator-general said the current anti-corruption momentum will not weaken. "We will continue the zero tolerance attitude toward graft," Cao said.

Although graft cases were on the rise last year, newly probed graft cases have been declining due to a higher threshold for corruption crimes.

Statistics released by the Supreme People's Procuratorate show that prosecuting authorities investigated 47,650 officials at all levels for duty-related crimes last year, down by 12.2 percent year-on-year.

"The decline is mainly caused by a higher standard for filing a corruption case, not because China has eased up in the fight against graft," said Hong Daode, a law professor at China University of Political Science and Law.

According to the newly amended Criminal Law, which took effect in November 2015, officials would face criminal punishment if they accepted bribes or were involved in another act of corruption valued at 30,000 yuan ($4,340) or above. The previous threshold was 5,000 yuan.

Jiang Laiyong, a senior researcher with the China Anti-Corruption Research Center at the Chinese Academy of Social Sciences, said that as the fight against graft has achieved "crushing momentum", the number of newly probed senior corrupt officials has decreased. However, more grassroots officials will be brought into oversight, Jiang said.

Cao required prosecutors to pay special attention to corrupt officials involved in buying and selling of official positions and those at the grassroots level who use their position to take in bribes. Chinese judicial organs will also enhance efforts to hunt down fugitives and confiscate their illegal funds sent abroad, he said.

zhangyan1@chinadaily.com.cn