Britain's online safety law risks suppressing free speech due to its heavy-handed enforcement, social media site X said on Friday, adding that significant changes were needed.

The Online Safety Act, which is being rolled out this year, sets tough new requirements on platforms such as Facebook, YouTube, TikTok and X, as well as sites hosting pornography, to protect children and remove illegal content. But it has attracted criticism from politicians, free-speech campaigners and content creators, who have complained that the rules had been implemented too broadly, resulting in the censorship of legal content.

Users have complained about age checks that require personal data to be uploaded to access sites that show pornography, and more than 468,000 people have signed an online petition calling for the act to be repealed.

The government said on Monday it had no plans to do so and it was working with regulator Ofcom to implement the act as quickly as possible.

Technology Secretary Peter Kyle said on Tuesday that those who wanted to overturn it were "on the side of predators".

Elon Musk's X, which has implemented age verification, said the law's laudable intentions were at risk of being overshadowed by the breadth of its regulatory reach.

"When lawmakers approved these measures, they made a conscientious decision to increase censorship in the name of 'online safety'," it said in a statement.

"It is fair to ask if UK citizens were equally aware of the trade-off being made."

X said the timetable for meeting mandatory measures had been unnecessarily tight, and despite being in compliance, platforms still faced threats of enforcement and fines, encouraging over-censorship.

It said a balanced approach was the only way to protect liberty, encourage innovation and safeguard children.

"It's safe to say that significant changes must take place to achieve these objectives in the UK," it said.

A UK government spokesperson said it is "demonstrably false" that the Online Safety Act compromises free speech.

"As well as legal duties to keep children safe, the very same law places clear and unequivocal duties on platforms to protect freedom of expression," the spokesperson said.

Ofcom said on Thursday it had launched investigations into the compliance of four companies, which collectively run 34 pornography sites.