Australia’s online safety watchdog said Tuesday it was considering court action against Facebook, Instagram, Snapchat, TikTok and YouTube alleging they are not doing enough to keep Australian children younger than 16 off their platforms.

Experts say the Australian courts could decide what steps the platforms can reasonably be expected to take under the laws that took effect on Dec 10 banning young children from holding accounts.

Julie Inman Grant, who is Australia‘s eSafety Commissioner, on Tuesday released her first compliance report since those laws took effect demanding 10 platforms remove all Australian account-holders younger than 16.

While 5 million Australian accounts had been deactivated, a substantial number of Australian children continued to retain accounts, create new accounts and pass platforms’ age assurance systems, the report said.

Inman Grant said in a statement her office had “significant concerns about the compliance” of half of those 10 platforms. Her office was gathering evidence against the five that they had not taken “reasonable steps” to prevent young children holding accounts.

Also read: From Australia to Europe, countries move to curb children’s social media access

Courts could order fines of up to 49.5 million Australian dollars ($33 million) for systemic failures to comply. eSafety would decide on whether to initiate court action against any platform by midyear.

Age-restricted platforms that aren’t under investigation are Reddit, X, Kick, Threads and Twitch.

Communications Minister Anika Wells said the five criticised platforms were deliberately not complying with Australian law.

“Social media platforms are choosing to do the absolute bare minimum because they want these laws to fail,” Wells told reporters.

Also read: Germany’s Merz open to social media ban for minors

“This is the world-leading law. We’re the first in the world to do it. Of course they don’t want these laws to work because they want that to be a chilling effect on the dozen countries that have come out since Dec 10 to follow Australia’s step,” she added.

eSafety had identified “poor practices” such as platforms allowing unlimited attempts for a user to pass their age assurance methods and prompting the user to try to pass the age assurance method even after they declared themselves underage.

Meta, which owns Facebook and Instagram, told The Associated Press it was committed to complying with Australia’s social media ban. “We’ve also been clear that accurately determining age online is a challenge for the whole industry,” the statement said.

Snap Inc, the parent company of Snapchat, said it has locked 450,000 accounts in compliance with the law and continued to lock more every day.

“Snapchat remains fully committed to implementing reasonable steps under the legislation and supporting its underlying goal of improving online safety for young Australians,” a Snap statement said.

TikTok declined to comment on Tuesday and Alphabet Inc, which owns YouTube and Google, did not immediately respond to a request for comment.

Lisa Given, an information sciences expert at RMIT University in Melbourne, said she expected the courts will decide whether platforms have taken “reasonable steps” to exclude young children.

“If a tech company has said: look, we put in age assurance, we’ve done all these steps. That’s reasonable. Even though the aged assurance technologies are flawed, whose fault is that? Should they be held accountable for a piece of technology that is not 100% and likely not going to be 100% foolproof any time soon?” Given said.

“That’s really the crux of it: what the courts will deem reasonable,” she added.

Reddit has filed one of two constitutional challenges to the social media ban in the Australian High Court. The other was filed by Digital Freedom Project, a Sydney-based rights group that did not immediately respond to a request for comment Tuesday..

Both suits claim the law is unconstitutional because it infringes on Australia’s implied freedom of political communication.

A prelimary hearing is set for May 21 when the court will set a date for oral arguments, Reddit said Tuesday.