Australia’s controversial new law barring under-16s from social media is one of the toughest crackdowns yet on platforms including Facebook and TikTok as governments worldwide grasp for ways to protect children from harmful content.

The new law will deliver a message to tech companies to "clean up their act," the country's prime minister has said.

The landmark Social Media Minimum Age bill sets Australia up as a test case for a growing number of governments. But opponents warn that young people may be driven to unsafe parts of the web.