Tech companies including WhatsApp and Reddit as well as streaming giant Twitch and gaming firm Roblox could be among more than a dozen sites added to Australia's social media ban for under-16s, the country's regulator said Wednesday.

Platforms such as Facebook, Snapchat, TikTok and YouTube were already included in the ban — a world-first.

But the head of Australia's eSafety Commissioner, Julie Inman Grant, has written to 16 more companies to "self-assess" whether they fall under the ban's remit.