Reddit is complying with the ban, but in its case will argue that the policy has serious implications for privacy and political rights. It is the second such legal challenge, with two Australian teens also awaiting a High Court hearing.

Various governments, from the US state of Florida to the European Union, have been experimenting with limiting children's use of social media. But, along with a higher age limit of 16, Australia is the first jurisdiction to deny an exemption for parental approval in a policy like this - making its laws the world's strictest.

Reddit said the law forces "intrusive and potentially insecure verification processes on adults as well as minors", isolates teens engaging in "age-appropriate community experiences" and creates an "illogical patchwork of which platforms are included and which aren't".