Meta co-founder and chief executive Mark Zuckerberg has cozied up to US President Donald Trump since the Republican was elected

San Francisco (AFP) - The former Facebook employee behind a scathing book about parent company Meta will testify Wednesday before US senators keen to establish whether the social networking giant ever collaborated with the Chinese government.

Former global policy director Sarah Wynn-Williams will allege the company explored breaking into the lucrative Chinese market by appeasing Beijing’s government censors.

“I witnessed Meta work ‘hand in glove’ with the Chinese Communist Party to construct and test custom-built censorship tools that silenced and censored their critics,” Wynn-Williams will say, according to testimony made public by the Senate committee.

“When Beijing demanded that Facebook delete the account of a prominent Chinese dissident living on American soil, they did it. And then lied to Congress when asked about the incident in a Senate hearing,” she will add.

Meta communications director Andy Stone told AFP Wynn-Williams’ testimony was “divorced from reality and riddled with false claims.”

“While (Meta CEO) Mark Zuckerberg himself was public about our interest in offering our services in China and details were widely reported beginning over a decade ago, the fact is this: we do not operate our services in China today,” he added.

The company’s family of apps is currently blocked in China.

Of particular interest at Wednesday’s hearing, headed by Republican Senator Josh Hawley of Missouri, is that Wynn-Williams contradicts what Zuckerberg has stated under oath during past congressional hearings.

Wynn-Williams’s book, “Careless People: A Cautionary Tale of Power, Greed and Lost Idealism,” was released on March 11 and became a bestseller despite Meta winning an arbitration court order barring the author from promoting the work or making derogatory statements about the company.

Her book recounts working at the tech titan from 2011 to 2017 and includes claims of sexual harassment by longtime company executive Joel Kaplan, a prominent Republican and ally of President Donald Trump who took over as head of Meta’s global affairs team this year.

Meta took the matter to arbitration, contending the book violates a non-disparagement contract signed by Wynn-Williams when she worked with the company’s global affairs team.

“The measure of how important these truths are is directly proportional to the ferocity of Meta’s efforts to censor and intimidate me,” Wynn-Williams will tell Senators.

“Careless People” ranks second on a New York Times bestseller list of nonfiction books, with another title highly critical of Meta close behind.

“The Anxious Generation,” which paints a dark picture of social media’s effect on children, is currently fourth on the Times bestseller list, a year after its release.