Tech giant Meta's shock announcement that it is ending its US fact-checking program triggered scathing criticism on Tuesday from disinformation researchers who warned it risked opening the floodgates for false narratives.

Meta chief executive Mark Zuckerberg announced the company was going to "get rid" of its third-party fact-checkers in the United States, in a sweeping policy shift.

"This is a major step back for content moderation at a time when disinformation and harmful content are evolving faster than ever," said Ross Burley, co-founder of the non-profit Centre for Information Resilience.

As an alternative, Zuckerberg said Meta's platforms, Facebook and Instagram, would use "Community Notes similar to X" in the United States.

Community Notes is a crowd-sourced moderation tool that X has promoted as the way for users to add context to posts, but researchers have repeatedly questioned its effectiveness in combating falsehoods.

Meta's announcement was cheered by conservative supporters of US President-elect Donald Trump, who said the move had "probably" been in response to his threats against the company and Zuckerberg.

Meta began fact checks in December 2016, after Trump was elected to his first term, in response to criticism that “fake news” was spreading on its platforms.

For years, the tech giant boasted it was working with more than 100 organisations in over 60 languages to combat misinformation. (Agencies)