Popular social media platforms Tiktok, Snapchat and Instagram are among the sites that will have to ban children younger than 16, with reforms likely to pass parliament by the end of the fortnight.
Federal Communications Minister Michelle Rowland introduced world-first legislation to the House of Representatives on Thursday, saying it would make the online environment safer for young people.
TikTok, Facebook, Snapchat, Reddit, Instagram and X (formerly Twitter) will have to impose age limitations on users.
But Messenger Kids, WhatsApp, Kids Helpline, Google Classroom and YouTube are expected to be classified as "out-of-scope services".
Prime Minister Anthony Albanese said the government wanted this "action to happen as soon as possible".
Opposition communications spokesman David Coleman said the social media companies had "abrogated their responsibility to care about Australian children" for too long.
"We look forward to working constructively on this legislation with a view to seeing it passed through the parliament next week," he said.
The office of the eSafety Commissioner said age assurance was important but had to be part of a broader approach.
"We must also continue working to ensure online services are safe by design and to build children's digital literacy, resilience and critical reasoning skills so that when they are of age to use these services ... they are equipped for the online world," it said.
The Australian Human Rights Commission said while the ban was designed to protect children from harm, it would likely have negative human rights impacts on young people.
"Where rights are limited to protect children from online harms, any limitations must be lawful, necessary and proportionate," it said.
"If there are less restrictive options available to achieve the aim of protecting children from harm, they should be preferred over a blanket ban."
The inclusion of messaging apps in the ban could have wider consequences by making communication within families harder, Ms Rowland said.
Companies that breach the minimum age obligation will face fines of up to $49.5 million.
"The bill ... does not provide the magic pill to resolve or eliminate every harm children face online, nor does it seek to rule out digital participation and inclusion for young people," Ms Rowland said.
"This is about protecting young people, not punishing or isolating them, and letting parents know we're in their corner when it comes to supporting their children's health and wellbeing."
Under the draft laws, social media platforms would be required to take reasonable steps to prevent children younger than 16 from having accounts.
There will be a minimum lead-in period of 12 months before the ban is activated.
Parents will not be able to give consent for their children to use social media, and users will not be required to hand over sensitive ID documents to platforms.
The measures will also allow the minister to exclude some services from the ban including messaging services, online games and health and education platforms.
Australia would be the first country to have an age ban on social media.
Age verification trials are underway to determine how the ban will be enforced.
