Thousands of Hong Kongers held rallies on Friday night, rejecting calls by the city's pro-Beijing leader to end their movement as the finance hub braces for another weekend of clashes, including a plan to disrupt the airport.

Police fired brief volleys of tear gas and rubber bullets against a few hundred protesters who had gathered outside a police station in Mongkok district.

The demonstrators later blocked roads, set barricades on fire and faced off with riot police before dispersing without any major new clashes.

But a second, much larger rally in the heart of the city's commercial district remained peaceful.

Millions of pro-democracy supporters have taken to Hong Kong's streets for the past three months in the biggest challenge to China's rule since the city's handover from Britain in 1997.

On Wednesday, Hong Kong's unelected pro-Beijing leader Carrie Lam surprised many by announcing she was scrapping a widely unpopular extradition law that sparked the massive and sometimes violent rallies, a major demand of protesters that she and Beijing had previously refused to budge on.

Lam portrayed the move as a bid to de-escalate tensions and start a dialogue.

But it has been widely dismissed by protesters as a hollow gesture after more than 1,100 arrests and many facing potentially lengthy jail sentences.

At the peaceful rally on Friday night in the city's business heart, many protesters said they planned to continue hitting the streets.

“It's too late now. In these three months, a lot of people have sacrificed themselves and been arrested,” a retiree who gave his surname as Cheng told AFP, bursting into tears.

A 26-year-old protester called Justin said withdrawal of the bill was “three months late”.

“I think the most crucial thing now is the excessive use of police force and there are no legitimate measures to deal with it,” he said.

Airport targeted

Protesters have said their movement will only end when other demands are met such as an amnesty for those arrested, an inquiry led by a judge into the police, and universal suffrage — all of which Lam and Beijing have rejected.

Online messaging forums used by the largely leaderless movement have called for protesters to “stress test” the airport on Saturday afternoon, filling up with suggestions for how to disrupt road and rail links leading to the terminals.

Last month hundreds of flights were cancelled over two days when crowds of protesters staged a sit-in at the airport, with ugly scenes as two men suspected of being Chinese spies were beaten.

Since then security has been ramped up around one of the world's major aviation crossroads and access to the terminals has been restricted to those with boarding passes.

But last Sunday protesters returned to the airport and showed they could still wreak havoc.

Operators of the Airport Express train suspended services after its station was besieged, while black-clad demonstrators built barricades at the bus terminus and attempted to stop traffic on the main road leading to the facility.

Stranded travellers were forced to drag their luggage along the airport road.

While the protests were ignited by the extradition law, they soon morphed into a wider movement calling for democratic reform and police accountability.

Hong Kong enjoys freedoms unseen on the Chinese mainland according to the “one country, two systems” principle underlying Hong Kong's return to China.

But many say those rights are being eroded by an increasingly authoritarian Beijing which has refused calls for Hong Kongers to directly elect their leaders.