BEIJING - Clues leading to corruption probes in China have mostly come from whistleblowers in 2012, an official with the Communist Party of China's (CPC) discipline watchdog said on Tuesday.

Of all the corruption cases handled by discipline watchdogs in 2012, the public has contributed 41.8 percent of the clues, according to Zhang Shaolong, deputy director of the letters and calls office under the CPC Central Commission for Discipline Inspection (CCDI).

People in China can write complaint letters, pay petition visits or dial hotlines to report corruption.

The Internet has played an increasingly important role in offering tip-offs in corruption cases, according to Zhang.

From 2008 to 2012, about 12 percent of the clues, or 300,100 items, received by the CCDI and the Ministry of Supervision, were collected via the Internet, the official said.