Twitter and other big social media firms have relied heavily on contractors to track hate and other harmful content.

But many of those content watchdogs have now headed out the door, first when Twitter fired much of its full-time workforce by email on November 4 and now as it moves to eliminate an untold number of contract jobs.

Melissa Ingle, who worked at Twitter as a contractor for more than a year, was one of a number of contractors who said they were terminated without notice on Saturday.

She said she was concerned there would be an increase in abuse on Twitter with the number of workers leaving.

“I love the platform and I really enjoyed working at the company and trying to make it better and I’m just really fearful of what’s going to slip through the cracks,” she said on Sunday.

Ingle, a data scientist, said she worked on the data and monitoring arm of Twitter’s civic integrity team.

Her job involved writing algorithms to find political misinformation on the platform in countries including the US, Brazil, Japan and Argentina.

Content moderation expert Sarah Roberts, an associate professor at the University of California in Los Angeles, said in a tweet on Sunday “3000+ contractor employees of Twitter were canned last night”.

Twitter hasn’t said how many contract workers it cut.

The company gutted its communications department and hasn’t responded to media requests for information since Musk took over.

Contractors also do other jobs to help keep Twitter running,

“All contractors are not content moderation agents,” Roberts said.

“Contractors fulfil many key roles inside the company but almost all moderation agents are contractors.”

Billionaire Tesla CEO Musk bought Twitter for $US44 billion ($A66 billion) in late October and dismissed its board of directors and top executives but assured civil rights groups and advertisers the platform could continue tamping down hate.

That message was reiterated by Twitter’s then-head of content moderation Yoel Roth, who tweeted that the November 4 layoffs only affected 15 per cent of the company’s Trust & Safety organisation (as opposed to 50 per cent cuts company-wide), “with our front-line moderation staff experiencing the least impact”.

Roth has since resigned from the company, joining an exodus of high-level leaders who were tasked with privacy protection, cybersecurity and complying with regulations.