China's graft watchdog unearthed a raft of problems at the country's securities regulator in recent years, including illegal share trading by officials' family members, prompting the head of the regulator to vow to eradicate corruption.

The revelations came at an internal meeting of leading Communist Party members in the China Securities Regulatory Commission (CSRC) amid a sweeping anti-corruption campaign launched more than three years ago by President Xi Jinping, according to a notice on the CSRC's website late on Tuesday.

Several senior CSRC officials were probed for suspected corruption during last summer's stock market crash, including former deputy head of the CSRC Yao Gang and assistant chairman Zhang Yujun.

The Central Commission for Discipline Inspection, the ruling Communist Party's corruption fighting body, said that in addition to illegal share trading by officials' relatives it had uncovered misuse of public funds, unauthorized travel abroad, private use of public vehicles and other violations, the statement said.

It did not indicate how many officials were involved or how widespread the problems were.

CSRC Chairman Liu Shiyu said the agency which oversees China's stock markets would bolster supervision of party members and eradicate corruption, it said.

In February, the party removed Xiao Gang from his role as head of the CSRC. Xiao had become a target of popular criticism following the market's ructions in mid-2015 and a further slide in share prices at the start of this year after botched attempts to check the volatility.