Australian teenagers have taken to social media for the last time to farewell their followers and mourn the loss of the platforms that shaped much of their lives before a world-first ban took effect on Wednesday.

In the hours leading up to the ban's midnight start (1300 GMT on Tuesday), a flurry of goodbye messages came from teenagers - as well as adults - on platforms including TikTok, Instagram and Reddit.

"I’ll miss you guys," posted 29-year-old Melbourne creator Josh Partington, who makes comedy sketches about Australian life for more than 75,000 TikTok followers.

Australia has ordered 10 major platforms including TikTok, Alphabet's YouTube and Meta's Instagram and Facebook to block around one million users under the age of 16 or face massive fines.

Some 200,000 accounts have already been deactivated on TikTok alone, the government said, with "hundreds of thousands" to be blocked in the coming days.

Young Australians, who have grown up using social media, faced the prospect of losing access to their favourite apps with a mix of sadness, humour and disbelief.

Also Read: Australia's social media ban for children takes effect in world first

"I’m going to miss you soo much and especially the funny content," one TikTok user wrote to their followers. "See you in a few years, but I don't know if my account will still be standing."

"Goodbye, see you on the other side," another said.

There were edits posted of users' favourite memes, while many urged their followers to join alternative platforms such as Yope, Lemon8 and Coverstar, which are not yet covered by the law.

On Reddit, users posted their goodbye notes to subreddits such as r/teenagers.

"As an autistic 13-year-old I am devastated," one popular post said.

"My playlist of 1,400+ songs on YouTube will be deleted and Reddit too, I have zero friends ... I will be completely alone for the next three years until I am 16."

Some stayed online until midnight on Tuesday, posting clips of clocks counting down set to Adele's "Skyfall" and its lyrics, "this is the end."

Others took their frustration out on centre-left Prime Minister Anthony Albanese, who has lost 6,000 followers across TikTok and Instagram since Tuesday.

"Just wait until we’re able to vote," one person commented on Albanese's TikTok account.

Not all teenagers were against the ban. "Ngl (not going to lie), social media ban is probably for the best of us," a TikTok user said. "All we do is sit behind a screen for hours."