Facebook hired teams of contractors to transcribe users' audio conversations

Facebook has hired teams to transcribe the audio conversations of its users. Photo / AP

Facebook has hired hundreds of extra staff members to transcribe the private conversations of its users.

The staff members were "rattled" by the work, according to Bloomberg, who reported that hundreds of external contractors were handed audio clips with no context and told to transcribe them.

The transcribers did not know why Facebook needed the audio from its users' audio conversations transcribed. According to the report, the audio occasionally contained "vulgar" content. The staff working on the transcriptions spoke to reporters on the condition of anonymity, as they feared Facebook would fire them if they spoke publicly about the work, reports news.com.au.

Facebook confirmed to Bloomberg that it hired contractors to transcribe the conversations of its users.

"Much like Apple and Google, we paused human review of audio more than a week ago," the company said on Tuesday.

The company explained users had clicked an option in Facebook's Messenger app, allowing voice chats to be transcribed. They said the role of the contractors was to check whether the company's AI technology was correctly identifying the user's speech, which Facebook say is anonymised.

Facebook has long denied the "conspiracy theory" that the company collects audio data from its users to assist in the servicing of targeted ads to those same users.

In US congressional testimony last year, CEO and Facebook founder Mark Zuckerberg addressed claims that Facebook recorded users' conversations.

Facebook CEO Mark Zuckerberg has previously denied that the company recorded users' conversations. Photo / AP

"You're talking about this conspiracy theory that gets passed around, that we listen to what's going on your microphone and use that for ads," Mr Mark Zuckerberg told Senator Gary Peters. "We don't do that."

Facebook has just paid a $7.358 billion ($US5 billion) settlement to the US Federal Trade Commission following an investigation into the social media giant's privacy practices.

According to Bloomberg, Facebook first started allowing users of their Messenger service to have their recorded audio conversations transcribed in 2015.

In Facebook's data-use policy, which underwent revisions last year, users are warned that "systems automatically process content and communications", however no mention is made of teams of transcribers listening to users' recorded conversations.

The policy does mention "vendors and service providers who support our business" by "analysing how our products are used".