The wife of a Chinese human rights lawyer said Monday she is suing the public security bureau for accusing her in an online propaganda video of fomenting "colour revolution".

Li Wenzu's husband Wang Quanzhang took on a number of civil rights cases considered sensitive by the ruling Communist party and was detained last summer.

His employer, Beijing's Fengrui law firm, was at the centre of last year's so-called "709 crackdown" which saw some 200 legal staff and activists detained.

A propaganda video posted last week to the social media account of a department of China's public security bureau accused activists of being in league with foreign organisations trying to undermine national security and foment "colour revolution" against the government.

It twice includes footage of Li calling for the return of her husband and of others detained.

The "colour" term is used to describe a series of anti-government revolts in the former Soviet Union and Middle East.

Over footage of Syrian refugees, the video said: "'Colour revolutions' have successfully turned many countries to war zones and strife, and the sharp claws of the devil have also reached China!", according to a transcript by civil society website Chinachange.org

The film takes aim at so-called "foreign forces" and the Chinese whom it claims are being used as their pawns.

Foreign NGOs, it proclaims, are "training proxies to lay the social foundation of a colour revolution", adding that mainland activists and Hong Kong's pro-democracy movement are part of a plot to overthrow the Chinese government.

Among the many "foreign forces" included in the movie is former US ambassador to China Jon Huntsman, shown predicting that the country's internet-savvy youth would "take China down".

The film also features footage from the trial of Fengrui director Zhou Shifeng -- a rights lawyer sentenced to seven years in prison for "subversion" this summer -- and pictures of him with foreign diplomats and journalists.

"The video wantonly defames human rights lawyers, deliberately distorting the truth, and also calls me an agent of colour revolution -- but I don't even know what colour revolution is!" Li told AFP, stating that she and her family were angry and scared.

"All I did was come out and look for my husband after he was disappeared, and they're calling this most basic response 'colour revolution', saying it's the equivalent of opposing the party, the government and all of society," she added.

She filed her suit on Sunday by post and will hear within the week whether a Beijing court will accept her case.

If Li really were an agent of colour revolution, "why not prosecute (her) in court, instead of wantonly smearing her" on social media, her court filing asked.

President Xi Jinping has overseen a wide-ranging clampdown on civil society since assuming power in 2012.