Westminster's digital, culture and media committee is calling for Zuckerberg to appear either in person or via video-link at a parliamentary inquiry examining how 50 million users' data was allegedly taken from Facebook and used in political campaigns.
Damien Collins, chair of the UK's House of Commons digital, culture and media committee said it was "appropriate" for the Facebook boss to explain himself. So far Zuckerberg has only agreed to send his chief technology officer, Mike Schroepfer or its chief product officer, Chris Cox.
In a letter to Damien Collins, Facebook's head of public policy, Rebecca Stimson said both men "report directly to Mr. Zuckerberg and are among the longest serving senior representatives in Facebook's 15-year history. Both of them have extensive expertise in these issues and are well placed to answer the committee's questions on these complex subjects."
However Damien Collins believes Zuckerberg should be there, albeit virtually: "We believe, given the serious nature of the allegations that have been made around the access and use of Facebook user data, that it is appropriate that Mark Zuckerberg should give evidence to the committee," he said at the start of a committee hearing.
"We will seek to clarify from Facebook whether he is available to give evidence or not, because that wasn't clear from our correspondence," Damien Collins said.
Facebook denies knowing data from its site was being used by British firm Cambridge Analytica, however an app downloaded by around 270,000 Facebook users gave the company access to data belonging to millions of their friends.
READ MORE: Dirty Tricks or Black Ops? The Secret World of Cambridge Analytica
Mark Zuckerberg recently paid for advertisements in US, British and German newspapers apologizing for the "breach of trust" but is still only prepared to send one of his deputies to answer questions at a House of Commons inquiry into fake news.
READ MORE: Facebook's Zuckerberg Apologizes for 'Breach of Trust' to Britons
It's alleged Cambridge Analytica harvested personal information from more than 50 million Facebook profiles without permission to build systems to target US voters with political advertisements.