A former official in Henan province has been placed under investigation over allegations he had indecent relations with a woman who he also stole money from, Chinese media reported on Tuesday.

The public security and Party discipline authorities in Shangqiu are investigating Zhang Minqiang, former director of the city's bureau for letters and calls, who is alleged to be involved in a sex and extortion scandal, local publicity department told Xinhua News Agency.

The bureau for letters and calls is a government agency designed to hear complaints from the public.

A number of photos and video clips have been shared on the Internet recently, suggesting that Zhang had an extramarital affair with a woman. Whistle-blowers claimed Zhang also extorted a huge amount of money from the woman who believed he could help her in businesses, the report said.

Zhang is also alleged to have intimidated the woman to stop her from reporting his misconduct to authorities, it added.