The wife of fallen former Interpol chief Meng Hongwei has expressed fears for his life and her own safety, lashing out at what she called the "cruel" and "dirty" Chinese government that arrested him in mysterious circumstances.

The comments by Grace Meng in a BBC interview represent a rare and extraordinarily blunt level of criticism of China's government by the victims of Beijing's tough crackdown on corruption, in which cases are typically wrapped up in secrecy and with only the official version of events coming to light.

"I think it is political persecution. I'm not sure he's alive," Grace Meng said in the interview conducted in France, where Meng was based at Interpol's headquarters.

Meng Hongwei, also a Chinese vice public security minister, went missing on a trip to China last month.

He subsequently resigned as head of the international police organisation on Oct 7 after Chinese authorities announced he was under investigation.

China has since said he is suspected of accepting bribes.

"I tell (my children) daddy is on a long business trip," the sobbing Grace Meng said, appearing in the interview only in silhouette to hide her appearance.

Complaining that there is "no limit" to China's power to act against opponents, she claimed to have received threatening phone calls suggesting she was being "targeted" in France.

"They are cruel. They are dirty," she said.

"I must stand up and I don't want any other wives and children like me."

The body investigating Meng, the National Supervisory Commission, can hold suspects for as long as six months without providing access to legal counsel.

Xi's anti-graft campaign has punished more than one million officials and has wide support from citizens fed up with endemic corruption.

But some analysts say it also enables the Chinese president to eliminate rivals.

One of the most powerful officials to fall was former security ministry chief Zhou Yongkang, who promoted Meng more than a decade ago and was sentenced to life in prison in 2014.

The relatives of fallen officials are typically silenced, and Grace Meng's outspoken advocacy on behalf of her husband is unprecedented and no doubt seen as an embarrassment by Beijing.

China has pushed to have high-level representation in international bodies.

Meng's Interpol appointment was seen as a major success in that drive, but political experts say his downfall is now likely to set back that effort.