Younger Australian teenagers on Instagram, Facebook and Threads are being told their accounts will be shut down ahead of the country's social media ban for under-16s.

Meta, which owns the three brands, said it had begun notifying users it believes to be between 13 and 15 years old by text, email and in-app messages that their accounts would start being deactivated from 4 December.

The ban in Australia comes into force on 10 December. It affects a number of platforms which also include TikTok, YouTube, X and Reddit.

Prime Minister Anthony Albanese said the "world-leading" ban was aimed at "letting kids be kids". Meta and other firms oppose the measure but said they would comply.

Australia's internet regulator has estimated there are 150,000 Facebook users and 350,000 teens on Instagram in the 13-15 age bracket.

From 4 December, children aged below 16 will not be able to create accounts on Meta's social media platforms. 

The company said it was asking young users to update their contact details so they could be notified when they became eligible to open an account. 

They can download and save their posts, videos and messages before their accounts are shut down.

Meta said that teens who said they were old enough to use Instagram, Facebook and Threads could challenge the restriction by taking a "video selfie" to be used in facial age scans.

They could also provide a driver's licence or other government issued-ID.

All these verification methods were tested by the UK-based Age Check Certification Scheme (ACCS) earlier this year, in a report commissioned by the Australian state.

While the ACCS said that all methods had their merits, it added: "We did not find a single ubiquitous solution that would suit all use cases, nor did we find solutions that were guaranteed to be effective in all deployments."

Social media platforms which fail to take "reasonable steps" to block under-16s face fines of up to A$50m (£25m). 

"While we are working hard to remove all users who we understand to be under the age of 16 by 10 December, compliance with the law will be an ongoing and multi-layered process," Antigone Davis, vice-president and global head of safety at Meta, told Reuters Financial.

Meta wants to see a law where under-16s have to get parental approval before they download a social media app. 

The firm told Australia's Seven News: "Teens are resourceful, and may attempt to circumvent age assurance measures to access restricted services."

But it said: "We're committed to meeting our compliance obligations and are taking the necessary steps to comply with the law."

Australia's e-Safety Commissioner, Julie Inman Grant, said the ban was aimed at proctecting teens "from pressures and risks they can be exposed to while logged in to social media accounts".

In a move seemingly to avoid being included in the ban, gaming platform Roblox this week announced that children under 16 would be unable to chat to adult strangers.

Mandatory age checks will be introduced for accounts using chat features, starting in December for Australia, New Zealand and the Netherlands, then the rest of the globe from January.

Which firms does Australia's social media ban apply to?

The e-safety commissioner has published a list of which social media platforms will be impacted by the age ban.

They are:

- Facebook

- Instagram

- Kick

- Reddit

- Snapchat

- Threads

- TikTok

- X (formerly Twitter)

- YouTube

Platforms not included are:

- Discord

- GitHub

- Google Classroom

- LEGO Play

- Messenger

- Roblox

- Steam and Steam Chat

- WhatsApp

- YouTube Kids