China has placed a provincial vice governor under investigation, officials said, the latest senior official to fall in a highly-publicised anti-graft campaign under the country's new leadership.

Guo Youming, vice governor of the central province of Hubei, was being investigated for suspected "severe violations of discipline and the law", said the ruling Communist Party's internal Central Commission for Discipline Inspection Wednesday.

The phrase is usually a reference to corruption.

Guo, 56, is the 13th official at vice-ministerial level or above to fall since new party chief and state president Xi Jinping came into power a year ago, according to Chinese media reports.

Xi has vowed to crack down on corruption at all levels of government, calling graft a threat to the future of the ruling Communist party.

But critics say the campaign has netted mostly low-ranking officials with only a handful of senior figures, and no systemic reforms have been introduced to increase transparency to help fight endemic corruption.

Guo is probably being probed for wrongdoings when he was the party secretary of Yichang city in Hubei, the China Business News said Thursday, citing an unnamed source with the provincial party discipline watchdog.

The most senior official to be swept up by the anti-graft campaign is Jiang Jiemin, director of the body that oversees China's large state-owned enterprises.

It was announced in September that he is being investigated for suspected "serious violations of discipline".

Other recent high-profile criminal cases pre-date the current campaign.

A court last month rejected fallen politician Bo Xilai's appeal against conviction and upheld his life sentence for corruption.

Former railway minister Liu Zhijun was given a suspended death sentence -- normally commuted to life imprisonment -- in July for taking 64.6 million yuan (now $10.6 million) in bribes.