Barristers for the federal government on Wednesday continued outlining seven risks posed by social media platform design features, as a two-day challenge to the ban continued.
The risks were addictive use, adverse sleep effects, depression, anxiety, suicidal ideation, exacerbation of disordered eating, and intensification of ADHD symptoms, barrister Joanna Davidson SC said.
The court is being asked whether limiting children and young people's political engagement outweighs the harm done by social media platforms.
The government maintains that the burden on the freedom of political communication was "indirect in nature and modest in extent", barrister Stephen Lloyd SC said.
The hearing before all seven justices began at the High Court on Tuesday.
Reddit barrister Perry Herzfeld SC argued the government's ban was "ill-targeted" and "over-broad", rejecting the US-based social media giant's inclusion as a banned platform.
Attending the first day of the hearing was Noah Jones, a 16-year-old founding member of The Digital Freedom Project, which launched the legal challenge before the ban began in December 2025.
A second challenge emerged days later from Reddit, which argued the ban raised issues on privacy and political expression and inaccurately captured the forum-based platform.
The ban bars children under the age of 16 from holding accounts on 10 digital platforms, including TikTok and Meta platforms Facebook, Instagram and Threads.
Snapchat, Kick, Reddit, Twitch, X and YouTube are also listed, but Discord, Whatsapp and Messenger are not age-restricted.
Speaking outside the court on Tuesday, Noah said young people should be able to share their views online, arguing that otherwise they would be "spectators in their own world".
"They shouldn't be shut out," he said.
The government has acknowledged concerns the bill might impinge on the rights of children, but believes the ends justify the means.
The ban's effectiveness has been frequently called into question.
A report by the eSafety Commissioner, which enforces the ban, in July said more than five million Australian accounts had been removed or deactivated.
But four in 10 children aged 10 to 15 remained active on social media three months after the ban began, down from 52 per cent.
Labor is pushing to pass its new digital duty of care bill, which would place the legal responsibility on tech platforms to proactively secure their systems rather than relying on users to report harms.