Reddit should not be considered social media, the app's management argues, as it fights Australia's world-leading ban for under 16s.
The company has filed a challenge in the High Court hoping to repeal the legislation, claiming the age limit is arbitrary, inconsistent, and threatens free speech.
A Reddit spokesperson said the platform was already complying with the ban, but warned it would force users to share more of their personal data, potentially including digital ID, to remain online.
The spokesperson also argued Reddit was not a social media platform, but a text-based discussion forum, and therefore shouldn't be included in the restrictions.
Reddit allows users to post photos and videos, comment on posts and direct message each other.
"While we agree with the importance of protecting people under 16, this law has the unfortunate effect of forcing intrusive and potentially insecure verification processes on adults as well as minors," the platform said in a post.
"This law is applied to Reddit inaccurately, since we're a forum primarily for adults and we don't have the traditional social media features the government has taken issue with."
Reddit is among 10 platforms included in the ban, which faces fines of $49.5 million if they fail to take reasonable steps to keep users under 16 off its site.
Its case is the second High Court challenge to the social media laws, with a separate case being brought by two teenagers, backed by the Digital Freedom Project, arguing the changes impacted on political communication.
Health Minister Mark Butler said Reddit's action wasn't surprising and vowed to fight it "every step of the way".
"The idea that this is some action by Reddit to protect the political freedoms of young people is a complete crock," he told reporters in Brisbane.
"What it is is action taken to protect the profits that they make, at the expense of the mental health of young people."
Mr Butler compared the legal challenge to the actions of big cigarette companies after Australia introduced tobacco control measures.
It comes as high-profile international figures come out in support of the new restrictions.
Prince Harry and Meghan, the Duchess of Sussex, say the ban is an urgent intervention that will help shield children from "unsafe and addictive platforms", but argue it's only a band-aid fix and does not tackle underlying issues with social media.
"This bold, decisive action to protect children at a critical moment in their development sends a strong signal that a child's mind is not a commodity to be exploited," they said in a statement on their foundation's website.
"The ban is an effective measure to stop imminent harm, but ultimately only works as a band-aid that does not address tech's broken design and exploitative business incentives."
Some teenagers have also expressed concern about their future as they grapple with the new age rules.
Carlee Jade Clements is a 15-year-old influencer from Melbourne who has 37,000 Instagram followers but is yet to be kicked off the platform, despite being removed from TikTok when the restrictions took effect on Wednesday.
She's clinging to her creative future but fears the rules will impact her income and opportunities.
The teenager has spent years building her Instagram following, with the account managed by her mother Simone.
It acts as a digital portfolio to showcase her acting, dancing and modelling, and has helped her land paid opportunities including brand deals.
But her followers and views have plunged as her predominantly teenage audience are kicked off the platform, with engagement metrics one of the main determinants of revenue from advertisers.
"It's taken years and years and years of work, and to take it away like that is devastating," Carlee said.
