Australia's world-first social media ban is taking effect on Wednesday, legally barring children younger than 16 from holding accounts with Facebook, Instagram, Kick, Reddit, Snapchat, Threads, TikTok, X, YouTube and Twitch.

The platforms face fines of up to 49.5 million Australian dollars ($32.9 million) if they fail to take reasonable steps to remove the accounts.

Meta, which owns Facebook, Instagram and Threads, was the first tech giant to react, beginning to exclude suspected young children from last week.

Sydney schoolboy Noah Jones, who turns 16 in August, is joining another 15 year-old as a plaintiff in a constitutional challenge to the law in the High Court.

The other in the case brought by the Sydney-based rights group Digital Freedom Project is schoolgirl Macy Neyland.

They claim the law improperly robs 2.6 million young Australians of a right to freedom of political communication implied in Australia’s constitution.

The Australian government is committed to defeating the challenge on behalf of what they say is an overwhelming majority of parents who demand government action against social media harms.

Many restricted children have told media they welcome their exclusion from platforms with design features that encourage them to spend more time on screens while also serving up content that can harm their health and well-being.

The parents’ group Heaps Up Alliance, that lobbied for the social media age restriction, backs the theory behind the blanket ban that “when everybody misses out, nobody misses out.”

Before Parliament passed the ban last year, more than 140 Australian and international academics with expertise in fields related to technology and child welfare signed an open letter to Prime Minister Anthony Albanese opposing a social media age limit as “too blunt an instrument to address risks effectively.”

Noah said the ban would lead to young Australians swapping from age-restricted platforms to more dangerous, less regulated options.

“I’m against this social media ban because as young Australians, we’ll be completely silenced and cut off from our country and the rest of the world,” Noah said. “We’ve just grown up with this our entire lives, and now it's just being taken away from us all of a sudden. We wouldn’t even know what else we could do.”

His mother, Renee Jones, is also involved in the court case as her son’s litigation guardian, because as a child he can’t make legal decisions himself.

She considers herself a relatively strict parent on social media, and never allowed Noah or his two older brothers to take devices into their bedrooms. But she supports Noah’s stance.

“My parents would never have dreamed that my children could be so fortunate to have this library of knowledge,” Jones said.

“But I really credit Noah as a young person who recognizes the dangers of social media. It’s not all sunshine and lollypops,” she added.

Digital Freedom Project president John Ruddick, who is also a state lawmaker for the minor Libertarian Party, said he had initially intended to apply for a court injunction in a bid to prevent the ban taking effect on Wednesday.

But his lawyers advised against it.

A directions hearing will be held in late February to set a hearing date for the constitutional challenge that will be heard by the full bench of seven judges.

Ruddick said the case wasn’t funded by any tech giant, but they would be “extremely welcome” to make a financial contribution.

Ruddick expected children would get around the ban by means including using virtual private networks to make them appear to be offshore.