An internet rights group launched a legal challenge Wednesday to halt world-first Australian laws that will soon ban under-16s from social media.

From December 10, Australia will force the likes of Facebook, Instagram and TikTok to remove all users under the age of 16 or face hefty fines.

The Digital Freedom Project said it had challenged these laws in Australia's High Court, arguing they were an "unfair" assault on freedom of speech.

"This ban is a direct assault on young people's right to freedom of political communication" the Digital Freedom Project said in a statement.

The group said it filed the legal case along with two 15-year-olds to represent millions of young Australians who would lose their access to the "modern town square".

"We are the true digital natives and we want to remain educated, robust, and savvy in our digital world," said one of those plaintiffs, Noah Jones.

"We're disappointed in a lazy government that blanket bans under-16s rather than investing in programs to help kids be safe on social media."

There is keen interest in whether Australia's sweeping restrictions can work as regulators around the globe wrestle with the dangers of social media.

Australia's Communications Minister Anika Wells said the government would not back down.

- Threats and intimidation -

"We will not be intimidated by threats," Wells told parliament on Wednesday.

"We will not be intimidated by legal challenges. We will not be intimidated by big tech."

Hundreds of thousands of adolescents are expected to be impacted, with Instagram alone reporting about 350,000 Australian users aged 13 to 15.

Meta, the parent company of Facebook, has started deactivating accounts based on information such as the age given when they were created.

Facebook, Instagram, Snapchat and TikTok are covered by the ban, as are streaming platforms Kick and Twitch.

Other popular apps and websites such as Roblox, Pinterest and WhatsApp are currently exempt -- but the list remains under review.

Social media companies have previously described the laws as "vague", "problematic" and "rushed".

The Australian government concedes the ban will be far from perfect at the outset, and some underage users will fall through the cracks as issues are ironed out.

But platforms face the threat of $32 million fines if they fail to take "reasonable steps" to comply.

On paper, the ban is one of the strictest in the world.

But some experts are concerned that the law will be merely symbolic because of the difficulty in implementing and policing online age verification.