Days after social media restrictions were implemented for children ... one of the banned platforms has announced it will challenge the laws in the High Court.

Apps like Facebook, Instagram and TikTok have set up age verification software to comply with the ban for kids under 16 years of age.

But in a notice on Friday, discussion forum Reddit said the law was unconstitutional - and it's been wrongly included.

It's the second challenge to the laws ... With two 15-year-olds listed as plaintiffs in another case backed by advocacy group the Digital Freedom Project.