Protests are expected to build outside Hong Kong's Legislative Council on Wednesday as groups that fear curbs on freedom of expression seek to block passage of the latest version of a proposed amendment to the city's copyright law.
It would clarify the use of online material.
The Hong Kong government began working on an update of the copyright law in 2006.
Opposition lawmakers had voiced few reservations to the latest version - Copyright (Amendment) Bill 2014 - until pressure groups launched a campaign last Saturday calling for lawmakers to reject it. The bill has been under consideration since June 2014.
The council's president, Jasper Tsang Yok-sing, said the vote on the bill would likely not take place before next week.
The first draft of the bill was introduced in Council in 2011, but it was voided when opponents in the body filibustered the final reading, which aimed to provide clearer protections for copyrighted material published on the Internet.
Netizens said it went too far and worried about their ability to use materials such as online videos and memes for parodies and satires.
Officials have assured opponents that the new proposal, in combination with existing clauses in the law, would give general Internet users better safeguards for nonprofit use of copyrighted materials. The new bill would introduce statutory exemptions for the purposes of parody, satire, caricature, pastiche, comments on current events and quotations.
A rally was set to start at 7 pm on Wednesday outside the council complex to demand that lawmakers use the filibuster tactic again. One of the local activist group called on supporters to wear black and prepare for "danger".
Although pro-establishment lawmakers are crucial for the vote, the protesters seemed to target opposition lawmakers who have refused to deploy the stalling tactic.
Secretary for Commerce and Economic Development Gregory So Kam-leung said the netizens' campaign largely misrepresented the bill. He told media on Monday that an open letter penned by a lawmaker failed to point out that infringement of copyright has always been subject to criminal penalties under current law.
Former lawmaker Ronny Tong Ka-wah lamented that the viral campaign by opponents wrongly said the new bill curbed free expression, as he found the outdated law a bigger threat. He attributed the eruption of fear to a lack of trust in the local government to uphold civil rights.
Police told media on Tuesday that they will deploy adequate manpower to uphold social order.