Pro-democracy legislators succeeded Wednesday in delaying a highly anticipated parliamentary debate over a new copyright bill in Hong Kong, which has been criticised as curbing freedom of speech.

Objections to the bill come as fears grow over the erosion of freedoms in the semi-autonomous city, with concerns that Beijing's influence is increasing.

The city remains deeply divided after mass pro-democracy rallies last year failed to force Beijing to back down on political reform, with the copyright bill the latest flashpoint.

The government says the bill -- already shelved in 2012 after opposition -- is necessary to help fight online piracy.

But critics slam it as "Internet Article 23" referring to an anti-subversion bill dramatically dropped in 2003 after half a million protesters took to the streets.

Political satire using a pastiche of song lyrics and movie scenes has long been common on the city's Internet forums and social networking websites.

Opponents fear the bill would set the stage for harsher government censorship online.

"We are happy to see it happening (the adjournment)," pro-democracy lawmaker Raymond Chan told reporters.

"The copyright amendment bill would affect every single Hong Konger. We are not ready," he said.

Another pro-democracy lawmaker Albert Chan, said: "The government should withdraw it to allow more time for the public to be consulted."

Leading groups from last year's pro-democracy rallies had pledged to gather at the government complex for the debate, with at least 1,000 expected.

After the adjournment they called off the rally and are expected to gather next Wednesday when the debate is due to take place.

The legislature was adjourned before the debate even began after a pro-democracy lawmaker requested a "quorum" call.

Legislators were discussing unrelated matters at the time.

With just seven democrats present and the pro-Beijing camp seemingly caught off guard, the day's business was successfully pushed back.

Thirty-five are needed for quorum in the 70-member chamber -- only 29 were there Wednesday.

Pro-Beijing lawmaker Tam Yiu-chung said he was disappointed that lawmakers from his camp "carelessly" showed up late.

Exemptions for parody, satire and commentary have been introduced since the original bill was shelved, but opponents are still sceptical.

Online commentators welcomed the delay Wednesday.

"It's awesome. Knowing this is an evil bill and will harm Hong Kong, it would make no sense to pass it," said one post on Yahoo News portal.

Once a British colony, Hong Kong was handed back to China in 1997 under a "one country, two systems" deal that guaranteed the retention of its civil liberties and capitalist lifestyle for 50 years.

But attacks on journalists, court cases against democracy activists and government interference in education have heightened concerns that the cherished freedoms are being lost.