A British AI firm said it was rethinking its "safeguards" after its audio tool was used to clone celebrity voices and have them say racist and homophobic slurs.

Eleven Labs tweeted on Monday that it had been a "crazy weekend" and admitted to finding "an increasing number of voice cloning misuse cases" just days after it released a demo version of the tool.

The firm did not give details of the cases but the internet forum 4chan was flooded with deepfakes of celebrity voices using racist, sexist and homophobic slurs.

Many of the posts mentioned Eleven Labs, with some users claiming to have been banned by the firm and others providing links to the demo version of the tool.

Celebrities who came in for treatment on the forum, which is notorious for its offensive humour, included the stars of the Harry Potter films, and film directors Quentin Tarantino and George Lucas.

Eleven labs has touted its voice cloning technology as having "the potential to revolutionise the way content is produced, delivered and interacted with across a range of industries".

In its publicity material, the firm produced a video of actor Leonardo DiCaprio being voiced by several other celebrities.

The firm tweeted that its technology had been "overwhelmingly applied to positive use" but said "additional safeguards" were needed.

Among the options it was considering were manually verifying each cloning request or tightening account verifications.

AI tools are trained on vast swathes of data -- pictures, audio, text or video -- that allow them to essentially predict what output the user would like.

Text tool ChatGPT has taken the world by storm with its ability to generate essays to a relatively high standard with just a few prompts.

Imaging tools like Dall-E 2 and Midjourney are threatening to upend the art and design world with their ability to generate complex images in the style of famous artists.

But critics have long expressed fear that cloning technology, particularly in audio and video, could lead to a flood of deepfakes and disinformation.

And several AI companies are facing lawsuits from people who allege the firms have breached copyright by using their material as a basis for the AI models.