Prominent figures in Hong Kong's protest movement say Chief Executive Carrie Lam's backdown on the controversial extradition bill won't stop the demonstrations.

After three months of protests, Ms Lam finally bowed to protesters' original demand to completely withdraw an extradition amendment bill which she'd previously declared was "dead".

But many protesters say it's "too little, too late", vowing to press on with demonstrations until their four other demands are fulfilled.

While the protest movement styles itself as "leaderless", key figures from across the generation divide have made it clear they don't trust Ms Lam is genuine.

Carrie Lam's withdrawal of the bill would have almost certainly been approved by China's President or senior officials. ( AP: Jae C. Hong )

"The intensified police brutality in the previous weeks have left an irreversible scar to the entire HK society. And therefore, at this very moment, when Carrie Lam announced withdrawal, people would not believe it is a 'sincere' move," activist Joshua Wong wrote on Twitter.

"In order for people to calm down, Carrie Lam has to respond to people's demands and of course many people would like to see the back of her — the earlier she goes, the better", Emily Lau, a veteran member of the city's pro-democracy movement, told ABC News Breakfast.

Ms Lam last week revealed in a private business event that her personal power to respond to the protests is "very, very, very limited" because her bosses in the Chinese Government view the demonstrations as a threat to national sovereignty.

So her move to finally withdraw the bill would almost certainly have been approved by China's President Xi Jinping or senior officials who answer to him.

While she also proposed dialogue sessions and made new appointees to a police watchdog body, Ms Lam affirmed she wouldn't concede to the other four demands, meaning the protests are likely to continue with no end in sight.

Mainlanders miffed by China's backflip on extradition bill

The Hong Kong Government's backdown on the extradition bill has raised perplexing questions in mainland China, with many social media users wondering how authorities went from hardline obstinance to giving in.

On China's largest public social media platform, Weibo, some users were questioning why violent protesters who would be jailed on the mainland appeared to get their way in Hong Kong.

"The Central Government has defined their actions as terrorism and is now satisfying their request? I can't stand for this! Is this compromising with terrorists?" a user named Xuyao wrote.

Other users on the highly censored platform pondered why the extradition amendment bill, which was backed by China's Government, would be withdrawn if it was as justified and needed as authorities claimed all along.

But overall anger is still mainly being directed towards the protesters, referred to as "separatists" and "thugs".

"The government has been forced to bow to the angry, violent youth, I hope the mainland boycotts Hong Kong," prominent commentator Zheng Haiwen wrote.

Many others were circulating theories on why China's Government has allowed the concession, with some pondering if the withdrawal of the bill and promises of dialogue may be an excuse to later send in security forces if the protests continue.

The headline of the China Daily's editorial said "protesters now have no excuse to continue violence".

"The SAR Government has given a chance to Hong Kong residents to replace antagonism and confrontation with peace and dialogue," the editorial said.

For most of the three-month unrest, China's Government has waged an intense propaganda campaign through its state-media outlets in an effort to convince audiences both at home and abroad that the protesters are largely violent, intent on separatism and backed by the CIA.

Now, in an almost surreal contrast to their earlier stances, some of the Communist Party's most loyal commentators have taken to social media to strongly declare their support for Hong Kong's Government withdrawing the bill.

"Support the Hong Kong SAR Government to withdraw the extradition bill," wrote Hu Xijin, the editor of jingoistic Communist Party outlet Global Times, who has spent the past three months strongly condemning protesters who sought that demand.

"I also call on Western media and politicians to support a turnaround in the situation of Hong Kong," he wrote.