Australia’s online safety regulator has put social media giants on notice, requiring them to explain what they are doing to to protect people from violent extremists and terrorists.

The country’s eSafety regulator announced on Tuesday that it had issued legal notices to Google, Meta, X, WhatsApp, Telegram and Reddit requiring each company to report on steps they are taking to protect Australian users of their platforms from extremist material online.

Accessing violent and extremist content on social media has been blamed for the radicalisation of the perpetrator of the 2019 Christchurch mosques shootings, which killed 51 people, and also a gunman who murdered 10 black Americans at Buffalo in New York in 2022. Both gunmen also livestreamed parts of their attack online.

According to Australia’s eSafety Commissioner Julie Inman Grant the risk of terrorism and online radicalisation remains high both in Australia and internationally.

She said in a written statement: “The tech companies that provide these services have a responsibility to ensure that these features and their services cannot be exploited to perpetrate such harm and that’s why we are sending these notices to get a look under the hood at what they are and are not doing.

“We remain concerned about how extremists weaponise technology like live-streaming, algorithms and recommender systems and other features to promote or share this hugely harmful material.”

The Commission said it had issued the notices under transparency powers granted under Australia’s Online Safety Act, which will require the six companies to answer a series of detailed questions about how they are tackling the issue.

Ms Inman Grant continued: “It’s no coincidence we have chosen these companies to send notices to as there is evidence that their services are exploited by terrorists and violent extremists. We want to know why this is and what they are doing to tackle the issue.

“And, disappointingly, none of these companies have chosen to provide this information through the existing voluntary framework – developed in conjunction with industry – provided by the OECD (Organisation for Economic Co-operation and Development).”

The companies have 49 days to respond and face financial penalties of around 780 thousand Australian dollars (£401,936) per day if they do not comply.

According to a recent OECD report, Telegram is the top ranked mainstream platform when it comes to the prevalence of terrorist and violent extremist material, with Google’s YouTube ranked second and X, formerly known as Twitter, third.

The Meta-owned Facebook and Instagram round out the top five.

WhatsApp is ranked eighth while a 2022 report by the New York state attorney general confirmed the Buffalo supermarket gunman’s “manifesto” cited Reddit as a platform that played a role in his radicalisation towards violent white supremacist extremism.

The eSafety Commission will also be asking Telegram and Reddit about measures they have in place to detect and remove child sexual exploitation and abuse.

The Commission said it will publish further information on the findings later in the year.