Video streaming giant YouTube on Wednesday attacked Australia's looming social media ban for under-16s, denouncing the world-first laws as "rushed" and unrealistic.

Australia will from December 10 ban users under the age of 16 from a raft of the world's most popular social media platforms and websites, including Facebook, Instagram, TikTok and YouTube.

"Most importantly, this law will not fulfil its promise to make kids safer online, and will, in fact, make Australian kids less safe on YouTube," YouTube public policy manager Rachel Lord said in a statement.

"We've heard from parents and educators who share these concerns."

YouTube, one of the most-visited websites in the world, was originally slated to escape the ban so children could watch educational videos.

But the Australian government changed tack in July, saying young users needed to be shielded from "predatory algorithms".

YouTube said all Australian users under 16 would be automatically signed out on December 10, using the ages linked to their Google accounts.

- Predators and peer pressure -

Underage users could still visit the website without an account, but would lose access to many of YouTube's features -- including "wellbeing settings" and "safety filters".

Lord said the "rushed regulation misunderstands our platform and the way young Australians use it".

"At YouTube, we believe in protecting kids in the digital world, not from the digital world."

YouTube said it would archive accounts so they could be reactivated when users turned 16.

"We will not delete or remove any of their existing content or data, and it will be waiting for them when they come back."

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

Australian Prime Minister Anthony Albanese has painted social media as "a platform for peer pressure, a driver of anxiety, a vehicle for scammers and, worst of all, a tool for online predators".

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.

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

An internet rights group last week launched a legal challenge to halt the laws.

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.